In 1933 archaeologist Robert du Mesnil du Buisson was searching beneath the ruins of an ancient Roman/Persian battlefield when he came across some siege tunnels that had been dug under the city. In the tunnels he found the bodies of 19 Roman soldiers that seemingly died while trying to desperately escape from something and one Persian soldier clutching his chest. Apparently when the Romans heard the Persians digging under their walls they began digging a tunnel of their own with the idea of dropping in on the Persians from above. The trouble for them was that the Persians heard it and set a trap. As soon as the Roman soldiers dropped through they were met with burning sulfur and bitumen which has the unfortunate effect of turning to acid in your lungs.