The great escape

The dramatic story of how Chinese guerillas rescued Donald Kerr, a young US pilot shot down over wartime Hong Kong, will soon be released as a movie. Zhao Xu met with Kerr's son to hear about his father's dangerous journey home.

For Dave Kerr, the discovery of two nails in the wall of a small kiln, or "charcoal cave", in the mountains of Hong Kong was a revelation.

"A charcoal cave is where wood is burned to make charcoal. Only one being used to hide someone would need a blanket as a door," the North Carolina native said. "My father wrote about the blanket in his memoir and although he did not mention the nails specifically, I can think of no other way to hold the blanket over the door except to use nails.