The Upper Xingú Rainforest is an area in the Amazon basin of Brazil. As the name suggests, it borders the upper reaches of the Xingú River. The area is inaccessible by road and tropical diseases such as malaria are endemic. It is inhabited by native tribes including the Yanomamo and Botocudo.
The Upper Xingú region was the target of the 1987 Whittlesey/Maxwell Expedition sponsored by the New York Museum of Natural History. The expedition's goal was to survey the poorly-explored region and search for traces of the mysterious Kothoga tribe.
The expedition left the city of Belém and traveled by Jeep and helicopter some two hundred miles up the Xingú. From there they continued up the river in dugout canoes towards the mesa or tepui called Cerro Gordo.
Many of the plants of the Upper Xingú region are unknown to botany. The Whittlesey/Maxwell expedition collected several crates of specimens but many of these were still uncatalogued as of the events of Relic. The region was the only known habitat of the Mbwun Lily.