Old San Juan is the capital of Puerto Rico. Old San Juan was established in 1521, making it the oldest city in the United States of America. The city's population is 323 thousand, which makes it the most populated commonwealth in Puerto Rico. The city features many famous sites, including the Castillo San Felipe Del Morro, a fortress left by the Spanish in 1898 when they were defending pirates and the Dutch from taking the land from them. The city features many other activities that are more trendy, including shopping, dining, and beaches. The City has many museums, including the Museo de Arte de Puerto Rico, which has some very famous paintings, including the oil painting of landscapes in Puerto Rico after they were hit with a devastating hurricane. These attractions make Puerto Rico one of the most famous places to visit in Puerto Rico, drawing in about 5 million tourists a year.