Scientists discover the secret to ancient Roman 'Gate to Hell'Two thousand years later, visitors should still be wary of Pluto's gate. Was it the bloodthirsty will of Pluto, the god of the underworld? The lower to the cave floor, the higher the amount of suffocating gas, which formed a lethal lake of carbon dioxide. Known as "Plutonium" after Pluto, it was thought to be a gate to the underworld and a way to convene with the god by offering animal sacrifices. Two thousand years later, visitors should still be wary of the gate; during the 2013 excavation, archeologists witnessed several birds drop dead after flying too close.

Source: Stuff February 23, 2018 01:30 UTC