Visitors are now able to stroll through the now-defunct Leicester-Swannington Railway tunnel and discover the history behind the historic structure.
The Glenfield Tunnel, built in the early 1800s, runs for a mile beneath Leicester's streets and has been closed since 1966.
David Lyne, from the Leicester Industrial Historical Society gave the group a guided tour of the tunnel, explaining its history and the project which has brought it back to life.
Leicester City Council bought it for just £5, and spent £500,000 restoring its crumbling walls to meet safety standards.
More top news
The NSPCC believes there are a number of reasons why there has been a dramatic increase in recorded child sex offences.
Armed police have carried out a raid apparently linked to Wednesday's deadly terror attack in Westminster.
Six addresses have been searched as part of police investigations so far and seven arrests have been made.