(From CubicDissection)
Leontev's 205 Minutes is a masterpiece in both design and construction. So named because if you make one correct move per second, non stop, it will take you 205 minutes to disassemble. This n-ary juggernaut requires over 12 thousand moves to disassemble. Once disassembled, a reset mechanism allows you to quickly bring it to the original state with only four moves. It also comes with the 136 minute piece which only requires around 8,000 moves to solve.

It was a difficult decision to make this puzzle. It's so incredibly complex and requires so much precision that I thought about it for well over a year. In the end I'm glad we made it...some puzzles are so genius they just have to be realized.