City on Caterpillar Tracks

This has nothing to do with astronomy or Universe Sandbox, but as a LEGO fan, I’m incredibly inspired by this creation:
http://www.brothers-brick.com/2010/02/19/crawler-town-brings-the-city-to-you/

Which seems to be directly inspired by fictional Traction Cities from Philip Reeve’s Mortal Engines Quartet series of books:
http://en.wikipedia.org/wiki/Traction_City

I think the idea of massive, movable cities is fascinating to think about.

Source: Brother’s Brick, an excellent LEGO blog.