Earlier today, the folks at PlanItMetro - the planning blog of Washington, D.C.'s transit authority - shared a snapshot of a bike rack in Buenos Aires.
If you look closely, "1 car = 10 bikes" is printed near the top of the rack. Based on the logo on the lower-left wheel, the rack appears to have been put in place by EcoBici, Buenos Aires' bike-share system.
This simple but clever design has been making its way around the world. A similar design by cyclehoop was originally commissioned for the 2010 London Festival of Architecture. It's also been spotted in Sweden.
An even earlier version comes from the Seattle Department of Transportation's bike parking initiative in 2009. It's a little rough around the edges, but the message still stands.