Quote McLaren_Field="McLaren_Field"How do the cranes get built so high in the first place ?
Do they lay them on the ground and pull them upright with ropes and lots of burly men in vests ?'"
Well, I've seen tower cranes being built by using mobile extending cranes on the ground but you couldn't do that with this kind of height.
I reckon that what you need to do is build a tower crane as normal.
Then when the building nearly as high as the crane, you use that crane to lift an extending crane on top of the building.
Then use that extending crane to build the tower crane even higher.
I'm a genius, me.
I could have got those planks across the gym in the Army Officers' initiative tests, easy.