Diffences between 20th century ballet and classical ballet?

20th century ballet is more modern than the typical plie, tondue, arabesk. It has awkward movements and turned in feet with arms out of typical position. The best way to put it is "Breaking Boundaries" a more contemporary dance than classical ballet. Contemporary ballet, you should watch it to understand more :) here's a link ---> http://www.youtube.com/watch?v=mF2k4RRfBb0