Skyscrapers are a common subject for LEGO models, and are modelled in a variety of scales. When built to 'minifig scale' they are particularly impressive due to the size of the construction, and the amount of detail the size and scale combination allows.
Two examples of LEGO skyscrapers are the High tech Office Tower and Sapphire Tower shown on Brickshelf.
It is also possible to build skyscrapers using a modular approach, as documented by Erik Amzallag. There is also a newer standard created by Bryan Bonahoom. Each modular in that standard can be one or more layers of 1x6x5 panels high.