Metropolis!

(via fredmiranda.com) The ultimate little boy's dream of toy cars come true (vimeo video).
The blurb reads:

After working on his newest project for four years, Chris Burden unveiled "Metropolis II" at the Los Angeles County Museum of Art (LACMA) in early 2012. This 20'x30' installation comprises 18 roadways, several train tracks, and various buildings constructed from Erector Sets, LEGO bricks, and Lincoln Logs. A pair of motorized conveyor belts generate all the potential energy to power the 1,100 custom-made cars (regular Hot Wheels proved too fragile), which travel around at a scale speed of 230mph. The result is an amazing frenetic energy that captures the rush of modern commuting in a big-city environment.

The dynamic sculpture has reportedly been sold for millions of dollars but will remain on display at LACMA for the next 10 years. Currently, "Metropolis II" may only be viewed during select 90 minute sessions, Fridays through Sundays.