i've always wondered this...

[amph1bius]

how do they take down those high cranes? how do they even get those giant counter-weight concrete blocks up there?

[CheapScotsman]

lego

[Odysseus_Maximus]

magic

[Anessa]

Transporter.

[UrbanPoet]

lego

yep... I saw it on a documentary once.
a bunch of big trucks come in, and they build it from the bottom up. :-0

[yuwing8]

god's mighty hand. the following picture might freak you out but I can vouge it is 100% real and authentic

http://www.intriguing.com/mp/_pictures/life/iii-hand.jpg

[Kommander_KornFlakes]

.
I work in this area. The crane is assembled by smaller cranes (trucks) and is placed on a platform. The weighs are placed at ground level by truck cranes. The crane has massive hydraulic lifts as "legs" and as a highrise building is being built the crane is lifted and dropped on the next floor higher up. This is done till they reach the 30th (or 100th floor). Then up in the roof they are dismantled with smaller cranes which are themselves brought by pieces on the elevators or even helicopters. There's usually a service elevator on the side of the highrise being built that's used for this.

It's like dismantling a truck and passing it through a house window and re-assembling it inside the house.
.

[amph1bius]

that is SO cool
my fascinations are satisfied

thanks for explaining

and i finally remembered to google it to find this

http://science.howstuffworks.com/tower-crane4.htm