Built between 1845 and 1855, El Fortín Conde de Mirasol (Fort Count Mirasol, Carr. 989, Isabel Segunda, 787/741-1717, www.enchanted-isle.com/elfortin/index.htm, Wed.–Sun. 10 a.m.–4 p.m.) was the last fort built by the Spanish in the New World. Never attacked or used in battle, it originally housed Spanish troops and later became a jail and execution site. Among those incarcerated here were fugitive slaves from local sugar plantations and political prisoners who sought Puerto Rico’s independence from Spain.

Later it was used as a municipal jail until the 1940s, when it was closed and fell into disrepair. In 1989 the Institute of Puerto Rico began restoration of the fort, which still has its original brick floors, exterior walls, and hardwood beams. Today the fort is home to the Vieques Museum of Art and History, home of Hombre de Puerto Ferro, the 4,000-year-old remains of a man whose body was discovered in an archaeological site near Esperanza, as well as exhibits dedicated to the island’s indigenous people, its historic sugarcane industry, and local artists. It also contains the Vieques Historic Archives.

Often referred to as Vieques Stonehenge, the archaeological site of Hombre de Puerto Ferro is on the south side of the island off Carretera 997. About 0.25 mile east of the entrance to Sun Bay, turn inland onto a dirt road that takes you to the fenced-off site. Giant boulders mark the spot where the remains were excavated in 1990. Some believe the boulders were placed around the grave; others say it’s a natural phenomenon.