Old San Juan is a historic district located in the heart of San Juan, North Puerto Rico. It is known for its charming cobblestone streets, colorful colonial buildings, and rich cultural heritage. The district is surrounded by massive stone walls and fortresses, including the famous Castillo San Felipe del Morro and Castillo San Cristóbal, which were built to protect the city from invasions. Old San Juan is a popular tourist destination, offering visitors a glimpse into the island's colonial past. The area is home to numerous historic sites, including the Cathedral of San Juan Bautista, the oldest cathedral in the United States, and the Paseo de la Princesa, a picturesque promenade along the waterfront.