One hundred kilometers northwest of the Yucatán peninsula there should be an island that did not exist. Isla Bermeja was first mentioned in 1536, when Alonso Chaves referred to it as “a small and maroon island in the Yucatan borders”. Since then, the island has appeared in most of the Gulf of Mexico maps. In 1775 doubts about its existence began. But it was still shown on the maps. In 2000, Mexico and the United States agreed with vigorous disagreements on the definition of maritime borders. The main problem was Hoyos de Dona in the Gulf of Mexico, an area rich in natural gas and oil. The existence of the island gave Mexico 80% of the area’s rights of use. But the island has not appeared. They thought of extravagant theories: the island sank due to a seaquake, disappeared due to global warming, was blown up by the CIA … In 2008 the Senado de la República Mexicana asked the government to organize an expedition to check the existence of the island. On March 20, 2009, a group of researchers from the Universidad Nacional Autónoma de México (UNAM) set out to find the island that would bring millions of euros to Mexico. After a week they found nothing on the surface or in the depths. According to INEGI and the director of the UNAM Institute of Geophysics, Jai me Urrutia, the idea of this island is based on a cartographic error that has been copied into the following maps and has not been checked. Despite these surveys, the Mexican government does not appear to be convinced. The issue is too sensitive for foreign policy to answer immediately. Nobody knows if this ever existed in the Gulf of Mexico. In May 2018, we set off to coordinate 22 ° 33 ‘N 91 ° 22’ E with a music band from the nearby city of Merida to play a hymn that a local composer wrote in honor of the island. The musicians played with nausea and vomiting on the ship, which anchored in the waters where the island could have been. These waters flow and are indefinite, while the sea borders are imaginary, well-defined and rigid lines.