A UNESCO World Heritage Site perched on a rocky headland at the entrance to Santiago's harbour, the Castillo de San Pedro de la Roca is the best-preserved example of 17th-century military architecture in the Caribbean. Construction began in 1638 and continued for decades; the result is a series of terraced platforms cascading down the cliff, bristling with cannon embrasures and connected by staircases cut into the rock.
The views from the upper terraces — across the harbour entrance, the open sea, and the mountains behind Santiago — are among the best in Cuba. The interior houses a piracy museum covering the privateers and buccaneers who plagued this coast for three centuries. It is 10 km south of the city centre; taxis are cheap and plentiful, or you can take a bus to the village of La Socapa and walk. Sunset from the battlements is spectacular.