Which chess tournament and venue has brought in the most people in the world?
According to the USCF, the record holder for largest attendance at a rated chess competition is the SuperNationals V with 5335 participants. Link
The SuperNationals III also had over 5000 participants, so this must be the recurring tournament that brings in the most people.
I think that it was the Cebu Chess Festival-World’s Largest Chess Tournament held in Ahmedabad, an Indian state, in December 2010. It had 20000 players and was led by Anand.