It is the fourth largest river in the world by discharge volume of water (39,000 m3/s at delta) due to the high precipitation throughout its catchment area (ca 2,300 mm/a).

The Orinoco, as well as its 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 1595, after capturing de Berrio to obtain information while conducting an expedition to find the fabled city of El Dorado, the Englishman Sir Walter Raleigh sailed down the river, reaching the savanna country.

From April to May 1800, the Prussian-born Alexander von Humboldt and his companion, Aime Bonpland, explored stretches of the Orinoco, supported by indigenous helpers and guided by his interest to prove that South America's waterways formed an interconnected system from the Andes to the Amazon.

Aboard a SR.N6 hovercraft, the expedition members followed the Negro river upstream to where it is joined by the Casiquiare canal, on the border between Colombia and Venezuela.

In the rainy season, the Orinoco River can swell to a breadth of 22 kilometres (14 mi) and a depth of 100 metres (330 ft).

The latter species, which is important in the aquarium industry, is also found in the Rio Negro, revealing the connection between this river and the Orinoco through the Casiquiare canal.

In 1926, a Venezuelan mining inspector found one of the richest iron ore deposits near the Orinoco delta, south of the city of San Felix on a mountain named El Florero.

Full-scale mining of the ore deposits began after World War II, by a conglomerate of Venezuelan firms and US steel companies.

[37]: 156  The El Furrial oil field was discovered in 1978, producing from late Oligocene shallow marine sandstones in an overthrusted foreland basin.

Starting out from Ciudad Bolívar or San Fernando de Apure, is the longest fluvial rally in the world with the participation of worldwide competitors, more than 30 support boats, logistics teams, thousands of tourists and fans travel.