Our phase one model of London used to cover 20km, it now extends to the M25 which is over 2000km. However, one of the demonstrators for phase one was the ability to morph the skyline and rise/lower buildings according to application.
The movie above demonstrates this with 30 St Mary Axe (The Gherkin) rising and sinking out of the ground to be replaced by various fictitious options. A simple movie, but one that hopefully demonstrates the value of a digital model (?)..