Cuba, the largest of the Antilles, is an archipelago consisting of a main island named Cuba, the Isle of Youth and about 4,195 keys and islets. Its elongated and narrow shape propitiates circulation of trade winds from the Atlantic, which cool its tropical, humid climate. Only one fourth of the land is mountainous being its main systems: The Guaniguanico mountain range at the west region; the Sierra del Escambray to the south centre of the country; and to the east the Sierra Maestra with its Pico Real del Turquino, climbing to 1,974 meters above sea level, the island's highest point. The remaining territory, plain and fertile, includes immense extensions of sugar plantations (the island's main export line), tobacco (highly appreciated worldwide) and other agricultural products.