A group of archeologists surveying an area in the remote Cagayan Valley on the Philippine island of Luzon come across some curiously shaped stones and bones scattered on the ground and decide to investigate further. After digging a few feet into the soil, an almost entirely intact animal skeleton reveals itself. They determine that the skeleton is from a rhinoceros and it has marks on its limbs and ribs. Was this rhino killed and butchered by someone in the Stone Age? Adventurers visiting Panama hike to Palo de Letras, an unmanned stone obelisk that marks the Colombia-Panama border, the invisible line separating North and South America. In the middle of nowhere, they stumble on an incomprehensible site ¬- a rusting wreck of a car abandoned to the jungle. The area is a stretch of tangled rainforest, mountains and swamps with no roads to speak of. How did a car end up in this treacherous region? Twenty miles from Sao Paolo, Brazil is the beautiful island Ilha da Queimada Grande. But if you look closer, this island paradise turns into something terrifying - it's covered with Golden Lancehead Vipers, between 2,000 and 4,000 of them. There are so many, some experts estimate that you'll find a snake for every three square feet. How did so many deadly snakes end up on this small island? Approximately nine miles from the Kenyan coast, surrounded by tropical forest, sits the impressive Panga ya Saidi limestone cave complex. There, researchers make a shocking discovery - human remains deep in the cave 10 feet below the surface. Who do these remains belong to?
