High above the waves, gazing over the Caribbean towards the European motherland, this 17th-century Spanish fortress could not have a more evocative position. Though its ruined remains are not that impressive visually, it's still an inspirational spot to reflect on the forces and characters that shaped the history of the American continent. Fifteen cannons face the sea, and a plaque marks the place where North American wannabe conqueror William Walker was executed. The on-site museum has colonial and Garifuna artifacts.