How long is a lap in Olympic swim meet?

A lap can be either 25 meters or 50 meters. In the Olympics and major National events the swim 'long course' which means the pool is 50 meters in length. However, there are still short course swim meets and the pool is only 25 meters. If you are talking about a track lap, it is 400meters! 25 METERS IT NOT THAT LONG. BUT WHEN YOU GET INTO IT YOU GET USED TO DOING MORE LAPS!!!