Puerto Rico is an unincorporated territory of the United States located in the Caribbean Sea. It is home to two major cities, Arecibo and PONCE. Arecibo is the largest city in Puerto Rico with a population of over 100, 000 people. It is known for its beautiful beaches, historic sites, and its Arecibo Observatory, which is the world's largest single-dish radio telescope. PONCE is the second largest city in Puerto Rico and is known for its vibrant culture, colonial architecture, and its many museums. Both cities are popular tourist destinations and offer a variety of activities for visitors.