You, Gadget Lab reader, love cranes. Of course you do — they can either rear majestically into the sky, balancing on a single flamingo-like leg, or offer the satisfaction of seeing a badly parked BMW lifted and towed off to an expensive overnight facility.

But unless you have stopped to watch a construction crane under, well, construction, you probably wonder just how the tall, slim structure gets up there in the first place. The answer is, of course, another crane, which puts us into a chicken and egg situation.

The above video will answer your questions (warning: hit mute before pressing play). There are a few tricks. The first is that the crane is actually rather short when the boom is put on, short enough that hanging one side before the other doesn’t tip the whole thing over. The second is that the huge concrete counter weights aren’t added until there is some weight to counter (obvious, really, when you think about it). And third, there is a lift system for adding vertical sections, meaning that the crane can be raised in place as the building grows.

The video was put onto YouTube by San Marco Cranes, an Italian company that sells around the world, and which also has a fascinating fascinating video demo of a self-erecting crane on its Canadian site. Also, did you know that a self-erecting crane costs $10,000 a month to rent, before adding any other costs? Were you aware of it?

Tower Crane Assembly with Climber Demo [YouTube via Noquedanblogs]