La Cabaña Fortress

Constructed after the capture of Havana by British forces and named San Carlos de la Cabaña in honor of King Carlos III, this 700-meter long fortress is the largest in the Americas. It was designed by army engineer Silvestre Abarca and features the most advanced military defensive concepts of the 18th century. It cost so much that King Carlos III requested a spyglass to see it, claiming that such an expensive project–approximately 14 million gold pesos–could surely be seen from Madrid.

Taken from Fortaleza de San Carlos de la Cabaña.