World Naked Bike Ride - in pictures

Hundreds of bicyclists in their underwear, covered in body paint or wearing nothing at all have taken to the streets of Mexico City to demand respect from motorists.

It's the sixth time Mexico City residents have participated in the World Naked Bike Ride, held in dozens of cities around the world.

Organizer Fabian Conejo said Saturday that riding nude demonstrates how vulnerable cyclists are to the millions of cars that clog Mexico City streets.

Conejo says that bike riding may be growing more popular in Mexico City, but that infrastructure projects to make bikers safer from madcap drivers and potholed streets has not increased apace.

Mexico City's government promotes cycling by closing off avenues to traffic on Sundays.

The London arm of the Bike Ride was also well attended, taking a route that passes many of the British capital's most famous landmarks.

Now in it's eighth year, the London event has seen participation grow from 58 in 2004 to 1,200 in 2009.