Most prestigious classical-music competition?

The Van Cliburn seems to be considered the Olympics of classical music, but the Chopin Piano Competition would give it a run for its money. Is there any higher-regarded classical-music contest than the Cliburn?

The “International Tchaikovsky Competition” has a lot of cachet as well. It got off to a flying start in 1958 when Van Cliburn won the piano segment.