Puerto Rico is a Caribbean island and an unincorporated U.S. territory. Two of its most well-known towns are PONCE and Arecibo. PONCE is the second largest city in Puerto Rico, located on the southern coast. It was founded in 1692 and is known for its colonial architecture and vibrant culture. Arecibo is the largest municipality in Puerto Rico, located on the northern coast. It is home to the world's largest single-dish radio telescope, which has been used to study distant galaxies and asteroids.