This is a video of an act from 1944 - a sister act called the Ross Sisters.
The song they sing is about 55 seconds long (nothing special) but what they do next is...!
I don't think I have ever seen a human being do some of the stunts they did!
Hope you enjoy it!
(Watch past the first 60 seconds or so, then Whoa! Look Out!)
Feast your eyes here below: 1944 America' REALLY Got Flexibility Talent