to the Yucatán Channel, and the northwest is open to the Gulf of Mexico. Nearly 4,200 islands, islets and cays make up the country. The southern coast includes such archipelagos as Jardines de la Reina and the Canarreos. The northeastern shore is lined by the Sabana-Camagüey Archipelago, which includes Jardines del Rey and is composed of approximately 2,517 cays and islands. The Colorados Archipelago is developed on the northwestern coast. Terrain Cuba's terrain is mostly flat or rolling plains, with rugged hills and mountains in the southeast. The lowest point is the Caribbean Sea at 0 m (sea level) and the highest point is Pico Turquino at , part of the Sierra Maestra mountain range, located in the southeast of the island. Other mountain ranges are Sierra Cristal in the southeast, Escambray Mountains in the center of the island, and Sierra del Rosario in the northwest. White sand beaches (most notably in Varadero), as well as mangroves and marshes can be found in the coastal area. The largest is the Zapata Swamp, with over . A recent global remote sensing analysis suggested that there were 675 km² of tidal flats in Cuba, making it the 38th-ranked country in terms of tidal flat area. Cuba has negligible inland water area. The largest natural water mirror is Laguna de Leche at , while the man-made Zaza Reservoir, at , is the largest inland water surface by area in the country. Geology Maritime claims Cuba makes maritime claims that include a territorial sea of and an exclusive economic zone of with . Extreme points Extreme points in Cuba are: Natural resources Natural resources include cobalt, nickel, iron ore, copper, salt, timber, silica, oil and petroleum. At one time the whole island was covered with forests, and there are still many cedar (Cedrela odorata), chechem (Metopium brownei), mahogany (Swietenia mahagoni), and other valuable trees. Large areas were cleared to grow more sugarcane, and so few trees remained that timber had to be imported. The most important Cuban mineral economic resource is nickel. Cuba has the second-largest nickel reserves in the world after Russia. Sherritt International, a Canadian energy company, operates a large nickel mining facility in Moa, Cuba. Another leading mineral resource is cobalt, a byproduct of nickel mining operations. Cuba ranks as the fifth-largest producer of refined cobalt in the world. Cuba has historically been dependent on oil imports. As of 2011, Cuba