“El Túnel de la Trinchera” corresponds to what is now identified as a deep trench with walls of smaller stones located in front of the fortress in an east–west direction.
The interior construction, also of stone masonry, preserved in perfect condition from the colonial era, have been restored with care and replacement roofs added.
Bringing a little more than a thousand men, the Portuguese strategy was to quickly build a fortified defensive line, south of Fuerte San Miguel to stop the Spanish invasion in progress.
The fort, designed by Gómez de Mello, consisted of a trench dug in the slope of a hill site, known as Chico Castillo.
The timber was moved from the area of Fuerte San Miguel, about 30 km distant, a daunting task for the time, because they had to ford countless streams and swamps.
However, in the war between Spain and Portugal, the Spanish general Pedro de Cevallos ordered the construction of another fort, directed against Portuguese Brazil, designed by Francisco Rodríguez Cardozo.
In 1776, a year after completing the construction of the Fortaleza de Santa Teresa, Portugal returned to threaten the Spanish in these parts of Latin America.
However, the total abandonment came about and it served to shelter cattle and bats, the latter inspired the former president Dr. Baltasar Brum to write a literary composition based on an Indian legend of the place.
In 1921, under Brum, the historian and archaeologist Horacio Arredondo conceived and proposed to restore it and preserve the Fort of San Miguel and the Fortaleza del Cerro in Montevideo.
"The Heart of stone siren" According to the legend: the spirits of the elements that inhabited the seas and land, after the triumph of Christianity there, migrated to our continent in search of tranquility, but they were discovered and lost their freedom.
Lovers of beauty and peace, they refused to fight against the human gods, and therefore, during a large gathering, decided to mutate in forms reminiscent of their passions.
The land spirits sought refuge in the flowers, trees, pines and insects, while the marine ones in capes, promontories, reefs, seaweed, dolphins and seals.
Metamorphosed into the Cerro Verde she suffers the eternal harshness of the North rejected lover, who, with the help of the sunrise and sunset, suppliers of sand, isolated her from the ground, by covering her with dunes.
The South prevents this, by circulating, with the caress of his breath, the sap that comes from the heart of the siren in order to give life to the lush green vegetation that covers her, in a triumphant defense of love over hate”.