San Juan is known as "La Ciudad Amurallada" (the walled city). San Juan was founded in 1521. In 1508 Juan Ponce de León founded the original settlement, Caparra, now known as Pueblo Viejo, behind the almost land-locked harbor just to the west of the present metropolitan area.
A year later, the settlement was abandoned and moved to the site of what is now called Old San Juan. San Juan is one of the biggest and best natural harbors in the Caribbean and is the second oldest city in the Americas.
San Juan is located in the Northern Coastal Plains region in the karst zone, north of Aguas Buenas and Caguas; east of Bayamón; and west of Carolina and Trujillo Alto.
San Juan is a major port and tourist resort of the West Indies and is the oldest city under the U.S flag. The metropolitan area known as San Juan has 3 distinct areas: Old San Juan, the Beach & Resort area, and other outlying communities, the most important: Río Piedras, Hato Rey, Puerta de Tierra, and Santurce. Río Piedras was founded in 1714 but became incorporated into San Juan in 1951.
During the early 16th century, San Juan was the point of departure of Spanish expeditions to charter or settle unknown parts of the New World. Its fortifications repulsed the English navigator Sir Francis Drake in 1595, as well as later attacks.
In the 20th century the city expanded beyond its walled confines, known as Old San Juan, to incorporate suburban Miramar, Santurce, Condado, Hato Rey and Río Piedras.
San Juan is the largest processing center of the island, the metropolitan area has facilities for petroleum and sugar refining, brewing and distilling and produces cement, pharmaceuticals, metal products clothing, and tobacco. The port is one of the busiest in the Caribbean. San Juan is the country's financial capital, and many U.S. banks and corporations maintain offices or distributing centers there. San Juan is center of Caribbean shipping and is the 2nd largest sea port in the area (after New York City).