It's almost impossible to imagine an entire city devoid of automobiles, but that is exactly what Amsterdam (aka the City of Bicycles) ordained on September 20th this year.
All the streets in the city (less a few arteries for exiting traffic) were reserved for pedestrians, trains and bicycles. On Autovrije Dag ("car-free day") the pedestrians owned the streets and the hum of the thousands of motors normally crowding Amsterdam's busy downtown area was completely absent.
Though there is a growing international Car-Free Day movement, Amsterdam is particularly well-adapted for bicycle and foot traffic. Unlike our American car-centric urban planning (just try crossing 3 blocks of lunch-time traffic in downtown L.A. and you'll know what I'm talking about) Amsterdam is designed for human-powered transportation.
Wide sidewalks, mini-bicycle freeways, and large plazas that double as bicycle parking lots have made bipedalism the preferred method of travel within the city. So for Amsterdamers that day wasn't a huge stretch, but it was nevertheless remarkable proof that a large city can function just fine without cars if it is designed to do so.
Car-free day coincided with the launch of the New Amsterdam Climate Initiative which has set for itself the ambitious goal of becoming carbon-neutral by the year 2015.
One of the highlights of the pedestrian street take-over was a big dance rave (remember those?) in one of the freeway tunnels. Check out Harald Walker's video montage of the day: