Sixty years ago, during the Cuban Missile Crisis, a provocative individual – probably a Cuban soldier – wrote a message in a system of bunkers and trenches on the Cuban coast stating that surrender was not in the cards , according to new research.

Archaeologists discovered the graffiti while documenting the remains of these bunkers and trenches, which Cuba prepared in case the United States invaded the island during the 1962 Cuban Missile Crisis – a 13-day stalemate that brought the world on the brink of nuclear war.

The individual’s message, written in Spanish, says he was determined to fight should war break out.

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The crisis, which occurred in October 1962 during the Cold Warignited when the Soviet Union placed nuclear missiles on Communist-controlled Cuba – about 124 miles (200 kilometers) from the US coast. The United States reacted by blockading the Caribbean island and threatening to invade it if the nuclear weapons were not removed, which brought the two nuclear superpowers closer to World War III. A deal was eventually reached in which the Soviet Union withdrew nuclear missiles from Cuba in exchange for the United States withdrawing nuclear missiles from Turkey.

Although the United States did not launch a full-scale invasion of Cuba, the system of bunkers and trenches that were built to defend the island remains. Some of the people stationed in these fortifications left defiant messages on the walls. “Some inscriptions relating to the time of the Missile Crisis are very interesting, including one that says: ‘aquí no se rinde nadie’ (no one gives up here),” said Odlanyer Hernández de Lara, a doctoral student in archeology at Maxwell School of Citizenship and Public Affairs at Syracuse University in New York, Live Science said in an email.

Archaeologists are documenting these Cold War defenses using 3D photogrammetry – a technique in which a multitude of digital photos are taken of an object and then processed by software to create a 3D digital model.

The system of bunkers and trenches formed an interconnected system of fortifications designed to prevent American troops from landing in Cuba. “These bunkers are concrete structures with a main embrasure and a raised/secondary embrasure [opening] facing the sea, and a main rear entrance with two alternative exits on the sides,” said de Lara. “The trenches are dug into the rock, connecting the bunkers with [a] storage area.”

Some bunkers and trenches are in good condition, but others have been damaged by coastal erosion or other effects of the passage of time, de Lara said. The Cuban military stopped using them some time after the Missile Crisis and they are now discontinued.

The research, which is not yet published in a peer-reviewed journal, was presented at the annual meeting of the Society for American Archeology (SAA) held in Chicago from March 30 to April 3. The SAA article was co-authored by Esteban Grau González-Quevedo, a researcher at the Antonio Núñez Jiménez Foundation for Nature and Humanity (FANJ), a scientific institution in Cuba.

Originally posted on Live Science.