Basejumper.com - archive

 A group of cavers exploring the Vietnamese jungle say they've come across the world's biggest cave entrance.
The massive passage, which measures 656 feet high and 492 feet wide, was found by a British-Vietnamese caving team this year in the country's Nha-Ke Bang National Park, according to a report in The Sun newspaper

http://news.aol.com/...iggest-cave%2F457044

I saw this a couple of days ago in the news. The pictures are incredible.

that's a remnant of the underground tunnels built by VC's, you know, Charlie, during the American-Vietnam war. Charlie did pretty good building that darn cave.

On the 9 line medevac request, line 8 is patient's nationality. The responses are A,B,C,D and E

A- US Military
B- US Citizen
C- Non US Military
D- Non US Citizen
E- Enemy POW

Notice Non US Military is Charlie, I'm not sure how long the 9 line medevac has been around, but as soon as I learned this I assumed it was probably where the term Charlie came from.

I'll take a stab:

Viet Cong -> VC -> Victor Charlie -> Charlie