Chimneys (specifically, the venting caps (“chimney pots”) on top of chimneys). Here's a Wikipedia image of similar chimneys in London: http://en.wikipedia.org/wiki/File:Chimney.stack.london.arp.j...

It's a bizarre world when people need to be told what a chimney pot is.

Not really. I've never seen anything like it here in the states before.

Huh, interesting. Seeing all of them there is oddly hypnotic.