Manaus, Brazil—Jochen Schöngart darts back and forth along an escarpment just above the Amazon River, a short water taxi ride from downtown Manaus, Brazil. It’s still early this October morning in 2023, but it’s already hot and his face is beaded with sweat. “Look, there’s a piece of ceramic!” he says, nodding to a worn shard lodged between boulders, likely a relic of an earlier civilization. It’s not the only one.