Which chess tournament and venue has brought in the most people in the world?
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.
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.