Discovery's website have some clips from their programme Prehistoric New York. It shows some of the spectacular prehistoric animals which roamed what is now New York city and shows how different the world was thousands and even millions of years ago.

Postosuchus:
http://dsc.discovery.com/videos/preh...nt-hunter.html

Archelon:
http://dsc.discovery.com/videos/preh...ea-turtle.html

Mastodon:
http://dsc.discovery.com/videos/preh...mastodons.html

Arctodus:
http://dsc.discovery.com/videos/preh...aced-bear.html

Castoroides:
http://dsc.discovery.com/videos/preh...nt-beaver.html