Professional British climber Tom Randall does a fair bit of urban free soloing, or free soloing buildings. The activity is often illegal and, as Tom Randall explains, sometimes sketchier and more dangerous than free soloing natural features. He also discusses different aspects that go into planning one of these climbs, from picking a location to considering time, in an upcoming episode of The Struggle Climbing Show.
Free soloing, on buildings or rocks, will always be an insane thing to watch, but it’s very interesting to hear where differences exist between the two. Again, this is from an upcoming episode, but if you want to listed to a whole load of great interviews on climbing, take a look at The Struggle Podcast (Spotify link).