The mostly unknown catacombs dating to the 1880s underneath Indianapolis' City Market are expected to be opened for public tours in a few months.
The brick archways, limestone columns and cavernous walkways span 20,000 square feet underground and were part of Tomlinson Hall, a building along Market Street in downtown Indianapolis that burned in the 1950s.
It isn't clear now why the catacombs were built and few people know they exist, said Stevi Stoesz, City Market's executive director.
"If you've sat on the plaza at City Market to have lunch and listen to a band, you've been sitting on top of this hidden gem," Stoesz told WTHR-TV.
Over the years, the catacombs have been used for storage, a few special events and once, during a severe winter storm in 1912, to house the homeless.
Some have suggested turning the area into a wine cellar, nightclub or an underground park, but Stoesz said a 1990s study estimated it would cost more than $7 million to make the catacombs meet safety codes. That work would involve grading out the area's dirt floor, removing potential asbestos and adding an elevator.
"We suspect that number is in excess of $10 million today, just to get them up to code," Stoesz said.
Limited tours of the catacombs offered by City Market and Indiana Landmarks during the week leading up to the Super Bowl this winter were such a hit that organizers plan to start offering more in June.
"We would show pictures of what stood before, Tomlinson Hall, and give a tour of the market as well," Stoesz said. "It's so shrouded in mystery and when people do learn about it, they want to learn more."