London's Mail Rail – It's been announced that London's Mail Rail -- once used to transport post beneath the capital -- will open to the public in 2017.
78 years of service – Operated by the UK's Royal Mail postal service, the service opened in 1927. It ran until 2005.
Hidden world – A sign displays the network of Mail Rail stations beneath the city. These were situated beneath the city's main postal sorting depots.
Mail map – A map shows the layout of some of the network, which stretched 23 miles from east to west across the city.
Abandoned carriages – Although the service was abandoned, mail workers still hosted occasional visitors, giving them rides in converted carriages.
Festive visits – At Christmas they took groups of children to visit Santa through tunnels painted snow white and bearing festive murals.
Starring role – The network doubled as a rail track beneath the Vatican for the 1991 Bruce Willis action movie "Hudson Hawk." This engine was painted yellow for its starring role.
Heavy traffic – At the height of operations, the fully automated service was carrying four million letters each day.
Deep beneath the streets – The rail tunnels, 70 feet (21 meters) below the streets of London, resemble miniature versions of London's Underground passenger network.
New beginnings – Some of the existing engines will be converted to carry passengers on a short stretch of track when the Mail Rail opens to the public.