"Here, look at this carefully," Fernando García says, as he opens his hands and reveals a treasure. "This is proof that humans, in reality, don't invent anything. Rather, they copy it from nature," he adds.
Between the biologist's fingers, a perfectly round shell gleams: a spiral shaped like a tiny staircase descending on itself, until it disappears into the center of the shell. "It's an impeccable golden ratio," he notes, before returning it to a shelf that's crammed with other shells. This particular shell was from a sea snail -- specifically, the species Architectonica maxima -- and is now part of the malacology collection of the National Museum of Natural Sciences (MNCN) in Madrid, where García works as an archivist.
Malacology is the branch of zoology that studies mollusks, a very diverse group of invertebrates that includes snails, octopuses and clams. And, of course, their shells, too. On the second floor of the Madrid museum, one of the world's largest collections is housed, organized into three major ecosystems: marine, freshwater and terrestrial. In total, there are nearly two million specimens.
"It all began in 1771," Francisco Javier de Andrés explains. He's also a curator of the MNCN archive. It was then that Carlos III of Spain received the donation of Pedro Franco Dávila's collections of natural specimens, which were used to found the Royal Cabinet of Natural History -- the seed that led to the current museum.
Since then, the shell collection has continued to grow. It was fueled, at first, by Spanish scientific expeditions to the Americas -- especially Cuba -- and the Philippines. When these missions returned, they were laden with exotic species, turning the archive into one of the most comprehensive on the planet.
Some of the pieces are preserved in a dry state. Others are kept in fluids: there are jars filled with alcohol that preserve the bodies of the mollusks that once inhabited those shells. They now rest in a dark room in the museum's basement. Some have been there for centuries. The oldest piece is a Pinctada margaritifera, also known as the black-lip pearl oyster. It was collected in 1758. "We believe that it may have belonged to the Royal Cabinet of Natural History since the institution's founding," De Andrés notes.
Many of the shells are shrouded in myths and legends. Between the aisles, García stops in front of a long shelf and decides to reveal a secret. "It's one of my favorites," he says.
What he shows EL PAÍS is a Conus gloriamaris, brought from the Philippines in 1777. "The region is a paradise for shells because it's a tropical archipelago that's highly-fragmented, producing currents with a lot of calcium carbonate -- the raw material from which mollusks make their shells," De Andrés explains.
Since the 18th century, the Conus gloriamaris has been the most valuable and coveted snail on the planet. "It's been said that it wasn't only the most beautiful and rare of the Conus, but also had the most beautiful of all shells," wrote the Spanish naturalist Florentino Azpeitia, in a 1927 scientific publication. A closer look is enough to understand why: a slender, cone-shapped silhouette -- measuring just under six inches -- is covered in a delicate network of dark lines on a yellowish background that appears hand-painted.
Until 1949, only 22 specimens of Conus gloriamaris were known in the world. In 1927, the price of one shell reached 6,000 French francs. In 1934, the MCNC obtained its own specimen from Azpeitia's personal collection. Word of mouth has it that, before the Spanish Civil War (1936-1939), the museum kept the specimen in a bank safe, so as to prevent it from being stolen. "We only know this through the oral tradition here at the museum, because we haven't found any documents to prove it... but it would have made sense as a way to avoid temptation," De Andrés clarifies.
This isn't the first time the value of a shell has been equated with that of a precious metal. Throughout history, various cultures have used shells as a form of payment. The best-known example is cowrie shells, which were used as currency in Africa, Asia and some Pacific islands. These shells were valued for their durability, portability and beauty. Their use as currency is explained by the fact that they were relatively scarce, easy to transport and difficult to counterfeit -- fulfilling many of the functions that, today, we attribute to money.
The collection is transformed into a labyrinth of stainless steel cabinets. Fireproof and waterproof, they're designed to withstand flames and floods. Each shell is stored in an acid-free polystyrene plastic container.
"Previously, they were housed on wooden shelves, which released vapors that -- combined with [high] temperatures and humidity -- were capable of dissolving the calcium carbonate in the shells," García sighs. The room isn't air-conditioned, but they hope to install equipment soon to maintain a constant temperature of 69.8°F and recreate an optimal ecosystem to preserve the shells.
"Tell me, what does this remind you of?" García asks, taking a pale pink shell in both hands and extending it forward. "It looks like porcelain, right?" He's holding a Harpa major... and yes, it could easily be mistaken for the finest porcelain. "Mollusks have historically served as inspiration for various human disciplines," the curator details. The fields of fashion, architecture, ceramics and even dance have used the shapes, colors and textures of snails to compose or design works of art.
At the end of the tour, the scientists head to a small room. In the center, there's a wooden table piled high with small snails and papers. "This belongs to a colleague who's researching a topic for his thesis; that's another function of the collection," García points out. With a careful gesture, the scientist moves the materials aside to make room for what he truly wants to show EL PAÍS. "This is where the terrestrial specimens are kept," he comments. Suddenly, the collection begins to reveal another kind of exoticism.
One highlight, for example, is the Papustyla pulcherrima -- a gastropod that lives in tropical rainforests and is endemic to Manus Island in Papua New Guinea. It's a small, bright green snail that resembles a precious stone. "Shells," García begins, "usually take on the colors of their environment, which is why marine shells have shades like sand. But in the case of terrestrial ones, things are different."
Each shell is a living architecture that the mollusk builds throughout its life, secreting minerals and proteins. In the case of the Papustyla, it's not known for certain where it gets its distinctive color. However, it's suspected that it processes plant-derived compounds and -- using its metabolic machinery -- transforms them into the green pigment that's deposited on the shell and gives it its color.
"It's all about trying to camouflage yourself, so you don't get eaten," García explains, while picking up a new shell. The Liguus fasciatus is a small, elongated, cone-shaped snail with a thin, smooth and shiny tip. Against a pearly background, brightly-colored bands -- green, yellow, brown, pink, or even purple -- unfold, running irregularly around the spiral, creating unique patterns.
After viewing a good portion of the collection, one question seems unavoidable. "Which is our favorite piece? Well, for us -- as biologists -- talking about a favorite piece is very complicated: they're all emblematic," García concludes.