Although the mouth of the Orinoco in the Atlantic Ocean was documented by Columbus on 1 August 1498, during his third voyage, its source at the Cerro Delgado-Chalbaud, in the Parima range, was first explored in 1951, 453 years later. The source, on the Venezuelan-Brazilian border, at 1,047 m (3,435 ft) of elevation (02�19?05?N 63�21?42?W ), was explored in 1951 by a joint Venezuelan-French team.
The Orinoco delta, and tributaries in the eastern llanos such as the Apure and Meta, were explored in the 16th century by German expeditions under Ambrosius Ehinger and his successors. In 1531 Diego de Ordaz, starting at the principal outlet in the delta, the Boca de Navios, sailed up the river to the Meta, and Antonio de Berrio sailed down the Casanare, to the Meta, and then down the Orinoco and back to Coro.
Alexander von Humboldt explored the basin in 1800, reporting on the pink river dolphins, and publishing extensively on the flora and fauna
