The oldest casino in the world, the Casino di Venezia, sits on the Grand Canal in Venice. Opened in 1638, it was originally a theatre called the Theatre Saint Moses, which had a wing for gambling during the intermissions of plays. It helped spark the start of a casino craze in Venice by 1744, there were more than 120.
Casino di Venezia is touted to be the world's oldest still active gambling establishment. Mauro Codussi was the architect of this casino that opened its doors for the first time in 1638. Interestingly enough, the building was a theatre and a part of it was reserved for gambling activities.