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If you needed any proof of the increasing popularity of robots, then look no further than Tatsumi International Pool in Tokyo, which recently played host to this year's underwater robot convention. Four times larger than last year's event in Kobe, the convention showed off over 80 H2O-friendly machines, including a snake that could move at 46cm per second, a sub that could dive to 1000m, and a craft that looked remarkably like the USS Enterprise.

There were four categories—Aqua-Bio Robot, Underwater Robot with Cables, Autonomous Underwater Robot and Radio-Controlled Submarine. And Tokyo's schoolkids got involved, competing to design the best water-based automaton. Check out 30 or so of the machines in the mahoosive gallery below.

2007 underwater robot convention in Tokyo Tatsumi international swimming place [Robot Watch]