The original Circle Line, marked yellow on any standard tube map, first opened in 1884. This makes it the third oldest line on the network, after the Metropolitan and District lines.
These days it is more of a lasso, but the extra track between Hammersmith and Edgware Road has not yet been absorbed into the classic ‘Circle Line Pub Crawl' route.
Uniquely on the network, the Circle Line has no individual stops, instead serving as a link line for the District, Metropolitan and Hammersmith & City lines in central London.
The original Circle line had 27 stations and covered 14.5 miles of track. With the lasso extension, which came into use in December 2009, it gained an extra eight stations and 2.5 miles of track.
Campaigns to officially change the line's name to Lasso have not yet been successful!