During the reign of Amadeo I of Spain (1871-1873) one of the most outlandish archaeological expeditions in history was carried out: the frigate Arapiles was sent to buy antiquities in the eastern Mediterranean to fill the halls of Spain’s recently inaugurated National Archaeological Museum (MAN). But there was one problem: the ship did not even carry enough funds to buy the coal needed to sail.

“Zero funds, help us minister with your legitimate influence,” the director of the scientific commission, Juan de Dios de la Rada, telegraphed from Constantinople. He did not receive a response.

Surprisingly, the mission achieved a measure of success, and the frigate returned to Spain with 319 archaeological objects, packed in 22 crates, along with 250 photographs and drawings. The question, however, remained: what exactly had they bought — or accepted as gifts? Nothing was entirely clear.

“Collecting implies choosing, an option that the commission to the East did not have. The compilation was not based on a specific and systematic research project. This methodological shortcoming aligns it more with illustrated collecting, but still far from a modern archaeological program,” writes the historian and Navy reservist, Carmen García, in The Archaeology that the Navy Brought by Sea. The Commission to the East of the Frigate Arapiles in 1871.

Winner of the last Don Juan Alvargonzález Naval History Prize, the book gives a detailed account of the ship’s odd journey that saw it cross the Mediterranean just when sailing ships were being abandoned in favor of steam power. The frigate had both systems, something that came in handy given the total lack of fuel. The crews had to wait for the winds to be favorable to begin the voyage.

At the end of the 19th century, Europe was creating its great museums, such as the British Museum and the Louvre. Spain launched the MAN. And although the great European museums filled their spaces with oriental objects, that was not on the cards for Spain; the country did not lead any of the great archaeological expeditions to the Middle East, which were mainly in the hands of the British, French and Germans. The Arapiles was presented as the solution. If you couldn’t loot, you could at least try to buy.

But soon the crew and the archaeological team came face to face with reality. “Today I only have 28 days of provisions left; the monthly payment in the box will barely suffice, a current monthly payment that, although I keep 520 tons of coal in the coal kilns, makes it absolutely impossible even using the sail as much as I can to travel the great distance that remains,” wrote the captain of the ship, who predicted that they would never reach Constantinople or Egypt, and the mission would fail.

Despite the challenges, the ship did, however, manage to reach present-day Turkey, where those on board discovered that other European countries were trading with Constantinople, while no ship with a Spanish flag was in evidence. They found that Italian, Greek, Austrian, French and English consuls lived in the finest villas in each of the country’s cities and invited local authorities to parties in huge palaces, something highly valued by the Ottomans. On the other hand, the Spanish diplomatic leaders resided in very modest houses where no high-ranking Turkish leader would deign to be seen.

When they went ashore, the culture shock for the Spanish expedition was severe. They understood absolutely nothing about Islam. In fact, one episode nearly triggered a serious incident: as a gesture of gratitude to some dockworkers, they offered them carefully wrapped pieces of bacon. For that reason, although the Spaniards were initially wary, the crew sought direct contact with the descendants of the Jews expelled from Spain four centuries earlier.

“On this trip to the East, the Sephardic Jews went from being a sector of the Ottoman population that was an object of official distrust, to being a group that the Spanish traveler valued for its hospitality and familiarity, making them feel at home,” says García.

The pieces that archeologist De la Rada acquired and that entered the MAN “were almost all gifts from the [Spanish and foreign] consuls, but not the vases that he acquired in Syracuse from his merchant friends who were gallant and attentive.” However, García adds that “Dr. Paloma y Romanas from the MAN affirms that the oinócoe [wine vessel] that was part of the grayish ceramic collection with black figures [that the expedition bought] is a forgery that managed to deceive De la Rada.”

The objects donated by the diplomats or otherwise acquired by the Arapiles included a large relief, a Greek stele (an upright stone or wooden slab monument), lanterns, a Roman head, torsos, fragments of marble sculptures, a Ptolemaic bust, a column from Pompey, ceramics, glass objects, coins and various statues. It was a not inconsiderable cache given the meagre amount of money available to the expedition.

Once back home, the Arapiles, which featured a wooden hull that could not support the armor it carried, ended up in Cuba and was scrapped. The ship cost 6.6 million pesetas but its wood and iron were sold for just 157,000 pesetas. Green, the U.S. shipbuilding company that sold the ship to the Spanish, was still demanding payment 40 years after the Arapiles was launched, claiming that the Spanish government had never paid for the frigate. Admiral Pascual Cervera responded: “I am almost absolutely certain that, if the books of the Green house are judicially searched, the sum they claim from us will be seen to have been paid.” Green did not insist again.

Carmen García wonders, given De la Rada’s denial of the forgeries, whether, on the right budget, he would have avoided such objects and bought instead only bona fide archeological pieces. Or if he would have fallen into a trap which García says is “as old as archaeology itself.” It is an unanswerable question, because he never had the chance to say, “I’ll take one of those mummies,” since the lack of funds meant he could never truly venture into the land of the Pharaohs. He only stopped in Alexandria — and only briefly and by sheer luck.

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The sperm of the fruit fly are enormous—the largest in nature relative to body size. The male Drosophila melanogaster rarely exceeds 1.8 millimeters in length. Its sperm measure the same — 1,800 microns. And it doesn’t produce just one, but thousands, which cluster in the seminal vesicle while they wait to encounter a female. After mating, the problem falls to her. These thousands of sperm cells end up in the spermathecae and the seminal receptacle. There they remain for up to two weeks before reaching the uterus and completing this delayed fertilization. Both organs are shorter than a single sperm cell. So how do flies keep them from getting tangled up? A theory first proposed in the 1970s — one that helped underpin the plastic age — has provided the answer.

A group of researchers has taken an in-depth look at how flies manage this. D. melanogaster is no ordinary insect: it is the most studied in science. Like mice among mammals, it is a key model organism and underpins much scientific and medical research (many human diseases have parallels in these flies). A team of physicists, biologists and mathematicians set out to understand how so many sperm — each 1,800 microns long — can fit into a space measuring just 200 × 150 × 150 microns, the volume of the seminal vesicle. Their findings, published in Nature Physics, show that the sperm are able to self-organize and generate movement through a physical mechanism.

Under the microscope, a human sperm cell looks like a tadpole: it moves on its own, beating its tail in a fluid medium, propelling itself forward as if swimming. It is programmed to do so. The sperm of the male fruit fly also moves under the microscope — it waves its tail — but it does not advance. What researchers discovered (see video above) is that its flagellum oscillates, but always in the same place. It only moves forward when it does so collectively: observed in the seminal vesicle, the sperm never stop moving in sync. What is striking is that, unlike in mammals, there is nothing in these sperm cells that makes them move autonomously.

“We found that two adjacent sperm in the male’s sperm-storage organ often swim in opposite directions rather than moving in the same direction,” says Jasmin Imran Alsous, from the Flatiron Institute in the United States. “This happens in any region of the seminal vesicle.”

It is as if they were gears: the oscillation of one in one direction forces, through contact, the movement of the other. “In one area of the vesicle, sperm can be aligned in a particular direction [even if they swim in opposite directions relative to each other], while in another area they can be aligned in a different direction [also maintaining opposite motion],” she continues. This dynamic allows the sperm to move without their flagella becoming tangled.

They appear to move like flocks of birds or schools of fish. But there are radical differences. “In those cases, the emergence of collective behaviors is often tied to sensory and behavioral cues such as vision, predator avoidance or a tendency to keep a fixed distance from others,” says Michael J. Shelley, also of the Flatiron Institute and senior author of the study. “That is possible because fish and birds are highly evolved organisms.”

He continues: “Individual sperm, as far as we know, have no communication system beyond mechanical interactions arising from their extremely dense packing. Therefore, the appearance of large-scale collective flows in these sperm aggregates is a mechanical consequence of their density and activity.”

In other words, a giant sperm cell that cannot move forward on its own — despite constantly beating its tail — manages to stay untangled and in motion only thanks to its interactions with its neighbors when packed in large numbers.

In nature, there are many examples of dense packing to make the most of space or of collective movement to gain efficiency. The DNA packed inside a tiny human cell can stretch to two meters. If the sperm whale, at nearly 20 meters long, is enormous, consider the length of its intestines — about 150 meters. And as for self-organized collective motion, in addition to bird flocks and fish schools, certain insect species — such as the black sawfly (Perreyia flavipes) — also move in coordinated groups.

“An isolated sperm differs from an isolated fish or bird in an important way. A fish can swim by itself, a bird can fly alone, and a mammalian sperm can also move individually,” Shelley notes. But the giant sperm of the fruit fly generate the typical bending waves seen in any sperm cell, yet remain motionless when isolated. “Hence both the large-scale flows and the rapid directional mobility observed in the seminal vesicle are the result of collective interactions,” the researcher concludes.

For the authors, this dynamic can be explained by the theory of polymer reptation. It was proposed by the French physicist Pierre-Gilles de Gennes in 1971. Developed in the years that followed, “it explains the most important phenomena in the use and recycling of plastics,” says Juan Francisco Vega, a researcher with the BIOPHYM Group at the Institute of Structure of Matter at Spain’s research center CSIC. Plastic is made of macromolecules that tangle and untangle during processing. “They move through an imaginary tube formed by adjacent polymers,” adds Vega, who did not participate in this study. Two decades later, Gennes would receive the Nobel Prize in Physics for his ideas on reptation and the physics of soft matter.

“But in this biological context reptation is active,” says Vega, who applies Gennes’s theory to ocular fluids and the design of eye drops: “Tears are made of highly confined macromolecules,” he notes. In plastics, molecules are passive; they move due to heat or an external force applied during processing. “By contrast, fruit fly sperm use their tails to writhe forcefully.” This self-organized movement — each one pushing against its neighbor — is, in Vega’s words, “the most efficient and fastest traffic jam in nature, where extreme density itself allows the system to function and not stall.”

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Until a few years ago, the true barometer of an artist’s or band’s popularity was recording an acoustic concert for the MTV Unplugged series. Today, that seal of approval has migrated to Tiny Desk — the short performances held behind an open desk at the U.S. National Public Radio (NPR) headquarters in Washington. Grupo Frontera reached that peculiar stage on April 24, 2025, performing five norteño ballads in 20 minutes, a set that allowed them to connect with a different audience. They rehearsed for six days to be ready for the appearance. “All the office workers see you,” recalls Alberto Acosta, the group’s guitarist.

That day, however, the most enthusiastic audience wasn’t in the newsroom — it was in NPR’s kitchen. The staff who prepare food and wash dishes couldn’t enjoy the performance because they were working. When the set ended, the six band members went back there to play El amor de su vida. It was a second Tiny Desk — improvised and intimate — that never appeared on NPR’s YouTube channel. “It was awesome,” Acosta says

This is a familiar scene for these musicians, who have become a phenomenon within regional Mexican music. At almost any restaurant they visit, whether in Mexico or the United States, the same thing tends to happen: a waiter will come over and ask them to step into the kitchen to greet the staff. “Our audience is working people — the folks out picking crops, the gardener,” says Juan Javier Cantú, the group’s accordionist. “In this industry, if you’re only in it for the money and the fame, it doesn’t work anymore, because you’re not connecting with your people,” he reflects.

A large share of their followers are workers who often go unnoticed by most people — those who labor in the back rooms of restaurants, raise buildings on construction sites, and keep gardens pristine in U.S. cities. It is also a community now living under pressure due to the tightening of immigration policies under the Donald Trump administration and the increase in raids by Immigration and Customs Enforcement (ICE).

The members of Grupo Frontera — a band formed in Texas, just a stone’s throw from the U.S.-Mexico border — say they are not immune to that reality. “We want all this fixed. Because what’s happening in our country is sad. We see it with our workers, with people close to us. It hurts us,” says Cantú.

They see the negative effects of Trump’s hard-line approach “closer than people think,” says the group’s singer, Adelaido Payo Solís III. The band’s drummer, Carlos Guerrero, agrees: “Those of us who live there [in the border city of McAllen] see it every day. It’s sad, but we’re fighting and standing strong.”

Days after releasing their new EP Con Dolor on May 28, the musicians spoke with EL PAÍS in a downtown Los Angeles skyscraper, where they were staying while taking part in World Cup-related events. They recorded a song tied to the tournament for a Spanish-language TV network.

Their time in the city was just a brief pause after a tour through Central America and Mexico. In a few days, they will head to Europe for shows in Paris, London, Zurich, Barcelona and Madrid, before wrapping up their Triste Pero Bien Cabrón tour at home in the United States. It is the most ambitious tour of their career and, for them, a sign of the global reach Mexican music has achieved — a phenomenon driven by artists such as Peso Pluma, Carín León, Natanael Cano and Fuerza Régida.

“Mexican music is at a point where it’s widely accepted in many places,” says Carlos Guerrero, the drummer. “Before, artists in this genre weren’t seen filling stadiums or arenas. The fact that our music has travelled this far — that we’re about to tour Europe — is something not everyone gets to experience. We take it with a lot of pride and a lot of respect.”

From local parties to massive concerts

Grupo Frontera’s rise has been nothing short of meteoric. In just six years, they went from playing at quinceañera parties in the Rio Grande Valley, Texas, to selling out large-scale concerts. Their breakthrough came in 2022, when their version of No se va went viral on social media.

But that was just the beginning. A year later, they made the definitive leap to stardom with UN X100TO, recorded as a duet with Puerto Rican superstar Bad Bunny. The scale of the hit is clear from the numbers beneath the video: more than 1.1 billion views on YouTube — and counting. “The collaboration with Bad Bunny helped the industry respect us more,” says Solís.

That same year, the Puerto Rican star invited them to share the stage at Coachella, one of the world’s biggest music festivals — another milestone in their career.

Despite their fame, they have remained close to McAllen, the border city where they grew up. They describe it as a place you can drive across in just 15 minutes — a far cry from the global cities they now tour. Back home, they are still surrounded by neighbors who speak Spanish and regularly cross into Mexico to shop, see doctors and enjoy the food. Rather than being a barrier, that environment shaped their artistic identity and led them to sing in their parents’ language, they say.

“Before, we used to say: for Mexicans, we’re not Mexican enough, and for Americans, we’re not American enough,” Solís recalls. “People would ask us: ‘How can you sing in Spanish if you don’t speak it?’ Well, that’s exactly what Selena did. She didn’t speak Spanish perfectly, but she sang in it. When we started, I kept improving my Spanish.”

The reference to Selena Quintanilla is no coincidence. In the 1990s, the so-called “Queen of Tex-Mex” paved the way from Texas for generations of artists raised between two cultures. She was one of the first figures to win over audiences on both sides of the border, at a time when much of the regional Mexican music consumed in the United States was coming from across the Rio Grande. Before her, Chalino Sánchez, from Los Angeles, had connected with migrant communities through corridos. Later came artists and groups such as Lupillo Rivera, Jenni Rivera, Intocable and Gerardo Ortiz.

Grupo Frontera’s rise coincides with a moment of uncertainty for the genre. In recent months, several artists — especially performers of narcocorridos — have seen their work visas revoked. The band members view the situation with concern, although they trust the outlook will soon shift for the better. “What happened to that famous ‘freedom of expression’?” asks percussionist Julián Peña, making air quotes with his fingers. “You’re supposed to be free to sing and talk about whatever you want in songs.”

Solís believes the worst is over. “At first it did feel heavier, both because of the visas and because people were afraid to go to concerts [because of ICE operations]. But I feel like things are improving.” In times marked by the immigration debate and political tensions, these musicians believe their cumbia songs serve a purpose beyond entertainment. “They’re giving strength to the whole community,” they say.

The group’s list of collaborations is long: Shakira, Maluma, Carlos Santana, Morat, Christian Nodal… They have moved between bachata, country, R&B, reggaeton and electronic music. Their next goal is to strengthen their own artistic identity, says accordionist Juan Javier Cantú: “We want to show little by little that we’re not just featuring artists.”

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