The Castillo de San Felipe de Lara sits at the narrow passage where the Río Dulce leaves Lake Izabal, a compact stone fortress that has been guarding this strategic bottleneck since 1644. Built by the Spanish to stop English pirates from raiding the cargo warehouses further up the lake, it was repeatedly attacked, burned, and rebuilt over the following century.
Today it is well-preserved and one of the most visited sites in eastern Guatemala. The three bastions, the drawbridge, and the thick walls are intact; a small museum inside covers the fort's history and the pirate conflicts of the 17th-century Caribbean. Boats stop here on the way between Río Dulce town and Livingston, or you can reach it by road from Río Dulce in a few minutes. On UNESCO's World Heritage tentative list.