We have been using Unity a lot ourselves recently as it provides a rapid way to visualise architecture and cityscapes. The movie above is running in Unity, detailed a real-time demo of Nordhavnen a city area located in Copenhagen, Denmark.
We especially like the change in scale halfway through the clip and the ability to change the shading on the buildings according to underlying data. The demo is developed by Utopian City_Scape who specialise in real-time visualisation of large city areas
See http://www.utopiancityscape.com for more information