Ciudad Perdida ("Lost City") is an archaeological site of an ancient city in Sierra Nevada, Colombia. It might have been founded as early as 5th century BC.

Ciudad Perdida was discovered in 1972 when group of local treasure looters found a series of stone steps rising up the mountainside and followed them to an abandoned city. They named it "Green Hell". When its gold figurines and ceramic urns begun to appear in the local black market, authorities revealed the site in 1975.

Members of local tribes - the Arhuaco , the Kogi and the Assario - have stated that they had visited it regularly but kept quiet about it. To them is it Teyuna, the heart of a network of villages inhabited by their forebears, the Tairona . It was probably the region's political and manufacturing center on the Buritaca River and may have housed 2000 - 8000 people. It was apparently abandoned during the Spanish conquest.

Ciudad Perdida consists of series of 169 terraces carved into the mountainside, net of tiled roads and small circular plazas. Entrance to the city is a climb of some 12.000 stone steps through dense jungle.

Unfortunately the area is in a middle of warfare between Colombian army, right-wing paramilitary groups (AUC) and left-wing guerilla groups like Ejército de Liberación Nacional (ELN) and Revolutionary Armed Forces of Colombia (FARC). In September 15 2003 ELN kidnapped 8 foreign tourists that were visiting Ciudad Perdida. ELN demanded government investigation of human rights abuses and released last of the hostages three months later. AUC has declared itself protector of the area. The Colombian Institute of Anthropology has also stayed away after the kidnapping. Access to tourists has also been restricted.