Explorers claim ruins found deep in a dense and dangerous Amazonian jungle could represent one of the great archaeological discoveries.
The multinational team has located the site in a remote region in central Ecuador.
They have already unearthed an 80m tall by 80m wide structure, made up of hundreds of two-tonne stone blocks, and believe there could be similar constructions over an area of about 2.6sq km.
Some of those involved believe the site in the Andes mountain range could be the mausoleum of Atahualpa, the last Incan emperor who was captured by the conquering Spaniards, or hold the Treasure of the Llanganates, a vast haul of gold and other riches amassed by his followers to pay for his release.
In exchange for his freedom, Atahualpa is said to have offered to fill a room with gold. But the offer was rebuffed and he was executed in 1533.