from wwh [Dr. Bill]:
I think there is a relationship between
'Ur-' as prefix, and city of UR in Chaldees (Bible)
one of the very early large cities.

Yep! [Thanks, Dr. Bill. Photos of ancient city on link below.]

This image is a reconstruction of the ancient city of Ur, established around 2100 B.C. as the capital of the Mesopotamian Civilization, which arose about 3500 B.C. The people of this civilization built a wonderful city, which was centered on a temple called a ziggrat that towered above all other buildings.

http://www.taisei.co.jp/cg_e/ancient_world/ur/aur.html