Venezuela has over 1,000 rivers, with the Orinoco River being the largest at 2,500 km long. The Orinoco splits into two branches and is joined by the Caroni River, which provides hydroelectric power. Approximately 27,000 people live in Venezuela today, with the largest ethnic groups being Mestizo (50%), Arab (29%), and people of African descent (10%). Venezuela was inhabited as early as 15,000 BC, and was colonized by Spain starting in 1498 when Columbus first arrived, with independence declared in 1811 but not fully achieved until 1821 after several battles.