City Model: GMJ based in London, UK

GMJ was founded in 1990 with a vision to reinvent the grand tradition of architectural illustration and model-making for the 21st century by pushing the boundaries of digital technology. -- GMJ web site.

Look at a video of 3D model of London .

City Model: 3D Model of Boston from BRA

Source: Boston Redevelopment Authority

Recently, the 3D model pages on Boston Redevelopment Authority(BRA) web site was updated. Here is the Link:http://www.bostonredevelopmentauthority.org/document-center?searchtext=&doctype=22