Ha, well, here's a little photo info about how tower cranes are attached.
I took this picture back in July of the construction of San Antonio's Grand Hyatt hotel.
I took this picture from the Tower of the Americas of the hotel's top during construction.
If you pan over to the right you can see the braces I'm talking about which anchor the crane to the building's skeleton.
I'm still wondering how these are attached though without damaging the concrete.