Located at the very southern end of the Windward Island chain and only 7 km from Venezuela on the South American continent, Trinidad and Tobago were populated by indigenous Amerindian tribes (the Arawaks and the Caribs) long before the arrival of Columbus in 1498. While Trinidad remained in the hands of the Spanish from the 15th Century until it became a British colony in 1802, Tobago was squabbled over by European powers. Just north of the Orinoco river delta in Venezuela, Trinidad is largely flat or undulating, ascending to a height of 940m (3084ft) in the Northern Range. Trinidad possesses sizable oil, gas and asphalt reserves, and its prosperity is linked directly to the production of petroleum and petrochemicals. The main surfing areas are situated in the north and north-east of the island near Toco, which is too far for a day-trip from Port-Of-Spain, but there is still a huge amount of coast line unexplored by surfers. Two thirds of Tobago is volcanic and mountainous, rising sharply in the east under a dense cloak of tropical rain forest, while the flatter, drier western side offers the nicest beaches. This southwest coast is where all the surf spots are located with the exception of Crazy's. The Buccoo Reef National Park is the main coastal feature, offering not only great surf but also fantastic snorkelling and diving.