There’s another, similar tunnel not far away, just south of the city, that is sometimes used by local contemporary music ensemble Champ d’Action for performances.
The one featured on Atlas Obscura (St. Anna Tunnel) is right in the center of the city so it actually sees quite a bit of pedestrian and bicycle traffic (especially in the summer, when people go to the left bank to chill by the water), but this one (Kennedy tunnel) is in an old and partly abandoned industrial zone. It’s not as sterile and straight but a lot creepier in a different way.
I’ve seen a performance with two Tibetan horns there, one at each end of the tunnel (about 600m apart); the sound seemed to roll back and forth like a huge wave. I’ve attended one where they had filled the tunnel with hundreds of tiny cages with tweeting mechanical birds, while a harpist was playing in the middle. I’ve been there alone at night and practiced “kargyraa” Mongolian throat singing. The acoustics are quite something!
