From Wikipedia

Lost Cities Of The Amazon

El Dorado is applied to a legendary story in which precious stones were found in fabulous abundance along with gold coins. The concept of El Dorado underwent several transformations, and eventually accounts of the previous myth were also combined with those of the legendary city. The resulting El Dorado enticed European explorers for two centuries, and was eventually found to be in Colombia.

Among the earliest stories was the one told by Diego de Ordaz's lieutenant Martinez, who claimed to have been rescued from shipwreck, conveyed inland, and entertained by "El Dorado" himself (1531).

In 1540 Gonzalo Pizarro, the younger half-brother of Francisco Pizarro, was made the governor of the provenance of Quito in northern Ecuador. Shortly after taking lead in Quito, Gonzalo learned from many of the natives of a valley far to the east rich in both cinnamon and gold. He banded together 340 soldiers and about 4000 Indians in 1541 and led them eastward down the Rio Coca and Rio Napo. Francisco de Orellana, Gonzalo’s nephew, accompanied his uncle on this expedition. Gonzalo quit after many of the soldiers and Indians had died from hunger, disease, and periodic attacks by hostile natives. He ordered Orellana to continue downstream, where he eventually made it to the Atlantic Ocean, discovering the Amazon (named Amazon because of a tribe of female warriors that attacked Orellana’s men while on their voyage.)

Other expeditions include that of Philipp von Hutten (1541–1545), who led an exploring party from Coro on the coast of Venezuela; and of Gonzalo Jiménez de Quesada, the Governor of El Dorado, who started from Bogotá (1569).

Parime Lacus on a map by Hessel Gerritsz (1625). Situated at the west coast of the lake, the so called city Manoa or El Dorado

Sir Walter Raleigh, who resumed the search in 1595, described El Dorado as a city on Lake Parime far up the Orinoco River in Guyana. This city on the lake was marked on English and other maps until its existence was disproved by Alexander von Humboldt during his Latin-America expedition (1799–1804).