Well, even if you dislike ovals (like me), you have to admit that Indy is the most famous in terms of pure name recognition...
Other than that (in no particular order):
Nurburgring (the original, not the little one they use now)
Does Bonneville count? it's not really a track, but.....
Sorry NASCAR fans.....the question was "...around the world" .....and outside North America, few people (if any) have heard of Darlington, Bristol, Talladega, Dover, Richmond, etc...even if they offer exciting racing.
A proud Yank who knows the world doesn't stop at the US border