The FINA World Championships (2006) consists only of the aquatic sports. It's more of an "elite" event, because the participants must achieve minimum qualifying times to enter.
The World Masters Games (2005) is held every four years. It's more than just aquatic events; it's a multi-sport festival similar to the Olympics. They say they have 17,000 total entries (all sports) so far. Anyone can enter; there are no qualifying times.
