10 enormous floating cranes

Aside from their spectacular size, what makes floating cranes unusual and interesting objects is that they are essentially boats. As such, they dont exactly conjure up the idea of stability, which is the primary requirement for lifting things. They also look weird since boats usually consist of large hulls with smaller superstructure, here the arrangement is reversed making them seem very ungainly.

Some of these cranes can lift tens of thousands of tons, at sea, and are engineering wonders.

 
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Here shown in England, lifting the Gateshead Millennium bridge into place.