The Spanish fort made of molluscs

If you build something with few resources, take what you have on hand. Some houses are built with mud and straw. In the Titicaca Islands, they are made with totora, an herb that grows in the lake. And how about building a fortress with mollusks? If we also talk about a fortress that has been searched for a long time, we have something important. The location of Fort San Anton de Carlos has been found. One of the first Jesuit missions in North America lived there. Made with mollusks in the Spanish fortress.

The mollusk fortress

It was built in 1566 in the capital of Calusa. It was the most powerful Indian tribe in the region. The location is the current mound key in the center of Estero Bay on the Florida Gulf Coast. It was built with mollusk remains and on a hill made of the same material.

The fort was suspected of being on Mound Key. The researchers have been looking for concrete evidence in the region since 2013.

“The only information we had came from Spanish documents. They suggested that the capital of Calusa be on Mound Key and that Fort San Anton de Carlos was there too, "said William Marquardt. He is Emeritus Curator of Archeology and Ethnography in South Florida at the Florida Museum of Natural History." Archaeologists collected pottery from the surface. But until we found physical evidence of King Calusa's house and fort, we couldn't be sure. "

The Calusas resisted European colonization for almost 200 years, said Marquardt. They are considered the first "mussel collectors" to use mussels as tools, utensils and jewelry. They built massive structures known as waterways that acted as fish pens.

The resistance of the Calusa

Investigators continue to ask how the Spaniards survived on Mound Key. The Spanish mollusk fortress is the only one built in this way. Fort San Anton de Carlos was abandoned in 1569 after the Spaniards' brief alliance with Calusa deteriorated. The Calusa left the island and the Spaniards too early afterwards.

“The Calusa have remained true to their values ​​and lifestyle. They showed greater resistance than other native companies in the southeastern United States, "added Marquadt in a statement.

Remote sensors, core extraction, penetrating radars and excavations were used to uncover the walls of the fortress. Artifacts such as ceramic fragments and pearls have been found.

The fort is also the first known American example of "tabby" architecture, an approximate form of reinforced concrete.

And it is a good example of how buildings adapt to the environment. Long before the term "sustainability" existed.