The Fortaleza de San Fernando de Omoa is the largest Spanish colonial fortress in Central America, a triangular bastion of cut coral and brick set back a few hundred metres from the Caribbean shore. It was begun in 1759 to defend the silver route from the British, the Dutch, and the pirates who used the Bay Islands as a base. The thick walls, the lookout turrets, and the powder magazines are all intact, and you can walk the ramparts for the long view back across the bay to Omoa village.
A small site museum displays cannon, shot, and finds from the fortress's working years, with displays in Spanish and broken English. The fort sits about thirty kilometres west of Puerto Cortés along the coast road and makes a comfortable half-day trip — combine it with lunch on Playa de Omoa, the long dark-sand beach a short walk away, where the seafront fritangas grill the day's catch.