The Thames Tunnel, the world’s first road tunnel under a river, was called the “eighth wonder of the world” when it opened in London in 1843. The storied passageway has been closed to the public since 1869, but now, thanks to the city’s Brunel Museum, it's getting a second life.

Last Thursday, the institution—which celebrates the tunnel’s designers, Marc Brunel and his son, Isambard Kingdom Brunel—re-opened the tunnel’s grand entrance hall for the first time in 147 years, The Guardian reports. The 50-foot-high sunken shaft will be used to host museum exhibitions, music performances, plays, and even weddings.

The 1300-foot Thames Tunnel was initially designed for horses and carriages to pass under the city’s famous river. Due to financial shortages, construction was never completed to build ramps for the vehicles. However, the Thames Tunnel became a popular pedestrian thoroughfare, receiving a staggering 50,000 visitors on its first day of service. City residents flocked to the tunnel, where they paid a penny to stroll through its gaslit depths, purchase souvenirs from vendors, and listen to musicians. At the time, it was the most successful visitor attraction in the world.

The East London Railway company purchased the Thames Tunnel in 1865; four years later, the famous feat of engineering was re-purposed into a railway tunnel, and was later incorporated into the East London line. In 2007, Gizmodo reports, the tunnel needed to be re-tracked. The Brunel Museum—which is housed in the tunnel's former Engine House—decided to convert the vast entrance hall into a cultural venue.

Today, the entrance shaft is finally accessible to the public, thanks to a new entrance and a freestanding, cantilevered staircase designed by architects Tate Harmer. It’s also been outfitted with lighting and sound equipment, and a grand piano. However, designers largely left the historic space alone. Its walls are still blackened from steam trains, you can still see an outline of the original staircase, and architects left behind a barred entrance pass where the Thames once burst through the tunnel during construction, killing six men.

“The space is a historic exhibit in itself,” Jerry Tate, a partner in Tate Harmer, told The Evening Standard. “It’s very raw and you can see the patina of history written on the walls. We haven’t cleaned it or tidied it at all.”

This week, opera singers will give two pop-up performances of Bellini’s I Capuleti e i Montecchi inside the Thames Tunnel. There, visitors can listen to the musicians’ voices echo through the birthplace of mass transit.

The Thames Tunnel is “the oldest tunnel in the oldest underground system in the world,” Brunel Museum director Robert Hulse told the Standard. “So this is the birthplace of the Tube. Which makes it the birthplace of world cities, because world cities couldn’t operate without mass urban transport. It all started here.”

Check out a timelapse video of the entrance shaft's renovation above.

[h/t The Guardian]