Nights in England are coal black, making parachute jumps difficult and dangerous. So we attach small lights called chemlites to our jumpsuits to make ourselves visible to the rest of our team. Late one night, lost after a practice jump, we knocked on the door of a small cottage. When a woman answered, she was greeted by the sight of five men festooned in glowing chemlites.

"Excuse me," I said. "Can you tell me where we are?"

In a thick English accent, the woman replied, "Earth!"