"driving on the Circle"
by cm

The Circle line, part of London's Underground, was completed in 1884, built by two rival companies, the Metropolitan Railway and the Metropolitan District Railway. It became known as the Circle line in 1949, although technically it is a "route" rather than a "line", as all its stations are shared with either the District or the Metropolitan line.

Circle Line, 2007
Creative Commons Attribution Share AlikeCircle Line, 2007 - Credit: David Cane