Sydney Opera house I'm guessing would be a pretty prime location for pokestops :o
International Landmarks seem to be pretty loaded with Pokestops/Pokemon
I was literally just about to make this topic though!!
I like to run around on the Santa Monica Pier since that's the one I heard the most about beforehand didn't fail to disappoint got a 90% Chansey first time I went
other than that I tend to run another account at the University closest to me since it has a tonnnn of Pokestops and used to be a Squirtle nest.. but I don't really see them there anymore so I've considered trying some new spots