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.
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Dry for much of the Wednesday with possible brighter spells in the east. Outbreaks of rain will spread southwards later in the day.
Wednesday will be another rather cloudy and mild day. Although dry for most the odd spot of drizzle is possible, mainly over high ground.