I don't know how far back you have to go but there was a time when you could find more bicycles than cars on the streets of many cities in the developed world.
It was still the case not that long ago in China.
Big cities around the world have started to bring back this light mode of transportation.
The biggest experiment so far must be Velib in Paris. Their site announces that 30 suburban cities around it are joining the program.
A few thousand sturdy bikes (picture above) have already been made available.
A conference aims to help expand this type of initiative to make towns and countries.
Named Velo-City, it takes place every other year. Previous one in 2007 was in Munich.
They describe the event as "generally considered to be the largest conference devoted
to cycling in the world. Cycling is a good, healthy, quick and
environmentally-friendly means of transport and the meetings being held
during the Velo-city conference will promote cycling as both a fun and
functional means of getting around."
It comes in many shades and flavors as their video below suggests.
Velo-city brings together policy makers, urban planners, bike companies, non governmental agencies and other non-profits to share ideas and hopefully implement a few.
From May 12 to May 15, Brussels is the host of Velo-city 2009.
On a fun note, for the traveler in you, if you want a guided tour of the French capital on 2 wheels, Paris à vélo c'est sympa! does just that from April to October. Choose between Paris at Dawn, Unusual Paris or Heart of Paris or even from May to September, Nocturnal Paris.
Don't sweat it!