Water Polo is the coolest real sport on the planet. It is played lengthwise in a 20mX30m pool. It is deep enough that you cannot stand on the bottom! Because the referees are not in the water, they have difficulty seeing everything that happens, so subtle pushing and holding is easy to get away with. This is one thing that makes it different from most other sports. The biggest difference is that in water polo a whistle, signalling a minor foul means GO!, not stop.