Fort San Cristóbal is a historic fortress located in San Juan, Puerto Rico. Built by the Spanish in the 18th century, it was designed to protect the city from naval attacks. The fort features thick walls and a strategic position overlooking the harbor, making it a key military installation during its time. Today, Fort San Cristóbal is part of the San Juan National Historic Site and is recognized as a UNESCO World Heritage Site. Visitors can explore its well-preserved structures, learn about its history, and enjoy panoramic views of the surrounding area, making it a popular tourist destination.