how do they make those tall cranes so TALL?

They come in sections. First few are fitted with a smaller crane anthe rest fit onto the side of the assembled base and are lifted up via the internal lifting mechanism then they just slot themselves into place forming another level containing a lift for the next piece and so on until the right height is achieved.

I'm sure that's how it works. either that or it's magic

with a taller crane. Some are over 600 feet tall.

Here is a great link from howstuffworks.com

piece by piece.