The city's colonial fortress is almost hidden amid the container ships and cranes across the harbor. The central part of the fortress was a prison, and a notoriously inhumane one, during the Porfirio Díaz regime. Today, San Juan de Ulúa is an empty ruin of passageways, battlements, bridges and stairways undergoing lengthy renovations. To get here, take a taxi (M$55) or a lancha (boat taxi; M$40) from the malecón (beach promenade).
The fort was originally built on an island that’s since been connected to the mainland by a causeway. The earliest fortifications date from 1565, and a young Francis Drake got his comeuppance here in a violent battle in 1569. During the colonial period, the fort and island became the main entry point for Spanish newcomers to Mexico.