The Castillo de San Juan, also known as San Juan Bautista, is a historic fortress located in San Juan, Puerto Rico. Built in the late 16th century, it was designed to protect the city from naval attacks and invasions. The castle features thick walls, a series of bastions, and a strategic position overlooking the harbor. Today, the Castillo de San Juan is a popular tourist attraction and part of the San Juan National Historic Site. Visitors can explore its well-preserved structures, learn about its history, and enjoy stunning views of the surrounding area. The site reflects the rich colonial heritage of Puerto Rico.