London Underground Buses, Tramlink, London Overground, London River Services and Docklands Light Railway. Crossrail, due to open in 2019, is to be identified with a roundel. The 100th anniversary of the roundel was celebrated in 2008 by TfL commissioning 100 artists to produce works that celebrate the design. Seventy of the 270 London Underground stations use buildings that are on the Statutory List of Buildings of Special Architectural or Historic Interest, and five have entrances in listed buildings. The Metropolitan Railway's original seven stations were inspired by Italianate designs, with the platforms lit by daylight from above and by gas lights in
London commuter belt East and South East regions. Most districts are entirely, or have sections, within the M25 motorway or are within of Charing Cross. Adjacent districts often share characteristics of Outer London, such as forming part of the continuous urban sprawl, being served by the London Underground, being covered by the London telephone area code, (until 2000) forming part of the Metropolitan Police District and having a relatively high employed population working in London. Larger Urban Zone is a definition created by Eurostat that measures the population and expanse of metropolitan areas across European countries. The population of London's Larger Urban Zone