No pants on the subway!

In New York and Mexico City, it was called No Pants on the Subway Day. In London, they called it No Trousers on the Tube. But for reasons that remain fairly vague, yesterday hundreds of commuters braved the freezing weather (well, chilly in Mexico City) to travel on their city's public transport system wearing nothing on their bottom half but their undies. The event was organised by a group called Improv Everywhere, who have been promoting the bottomless travel day since 2002.