Near the gardens stands Great Britain's first internally illuminated street sign called the "Pillar of Salt". When built, it needed permission because it did not conform to regulations. Bury St Edmunds is where the A1101 road, Britain's lowest road, ends. There is a network of tunnels which prove that chalk-workings took place nearby, though there is no evidence of a lot of tunnels under the town centre. Some buildings have cellars which lead into each other. Due to their unsafe nature the chalk-workings are not open to the public, although viewing is allowed to some people. Some tunnels have caused subsidence in living history.