What are some chess tournaments around the world that have both Grandmasters and non-professionals players in the same section? I want to enter chess tournaments were there are titled players from more than one country and where non-titled players can compete in the same section.  Where can I find such open tournaments and what are the details?
I usually find my tournament in this online chess tournament calendar.

If you visit the homepage of a tournament you can often check who already registered and who is eligible to participate. 

Another easy way to make sure your conditions are met is just checking the prizes. In Europe a thousand euro first prize usually means there are going to be GMs participating. If there are several thousand euro first prize you can be sure that there will be many GMs and other strong players from all over the world.