subway systems of the world, presented on the same scale

Great perspective. I'm also thrilled that the designer saw fit to include the entire PATH system along with the NYC subway. In fact, he went so far as to include the light rail into Jersey City.

I've ridden on the following subway systems:

London
Paris
Stockholm
Washington, DC
San Francisco
Los Angeles (apparently nobody else does)
Montreal (actually, that's a lie. my friends and I tried to find this elusive subway but it was like a phantom. nobody wanted to talk about it.)
Boston
Brussels