A secret network of tunnels 100ft (30m) under central London has gone on sale.
The Kingsway Tunnels were built in 1940 as deep air-raid shelters which could accommodate 8,000 people.
They have since been used as a public record library and a telephone exchange. The Post Office took over the tunnels after World War Two.
Now its successor, BT, is selling the 77,000 sq ft of space, and the firm hopes the sale could attract offers of about £5m.
Access to the mile-long system of horizontal and vertical shafts is through unmarked doors in the street on High Holborn.
See full story and pictures at http://news.bbc.co.uk/1/hi/in_pictures/7672341.stm