Somewhere in the Amazon, legend insists, lies a city built on gold: El Dorado. This Myth Hunters episode traces the belief from Spanish conquistadors who first heard tales of a golden kingdom through to Colonel Percy Fawcett, the British explorer who staked his reputation and eventually his life on finding it. The film follows Fawcett's expeditions into the Brazilian jungle, his conviction that ruins of a lost civilization lay hidden beneath the canopy, and his disappearance in 1925 while searching for what he called the City of Z. Historians and explorers weigh the evidence behind the legend against what modern archaeology has actually found in the Amazon basin, including signs of large pre-Columbian settlements that complicate the simple myth-versus-reality framing. Maps, expedition photographs, and location footage of the jungle terrain fill out the narrative alongside expert interviews. The episode treats El Dorado less as a treasure hunt and more as a case study in why an obsession can consume an otherwise rigorous mind.