Arecibo is known as El Diamante Del Norte,“The Diamond of the North”. Located on the northern coast of Puerto Rico, on the shores of the Atlantic Ocean, the town is about 50 miles west of San Juan. The temperature is typically in the mid-80’s during the day and low 70’s in the evening. Nearby beaches include Los Morillos, Los Negritos, Poza del Obispo, and Las Tunas. Because of the wide beaches and beautiful waves, surfers are drawn here. Nearby, there are two forest reserves. Cambalache State Forest is located in Barceloneta. Rio Abajo State Forest is located between Arecibo and Utuado. Caves include Cueva Ventana, which overlooks a valley formed by the Rio Grande de Arecibo, and La Cueva del Indio (Cave of the Indian), where paintings made by prehistoric indigenous peoples have been seen. Nestled in the mountains is theArecibo Observator the world’s largest and most sensitive radio telescope used to study stars, galaxies and the earth atmosphere. Until July 2016, the telescope was the world’s largest radio telescope. Built by the Spaniards in 1898, Arecibo Lighthouse is still in use today. A museum with exhibits, a recreation area, a restaurant and sports facilities are all located here.