What is this creepy sound from downtown Calgary?

Calgary is notorious for weird, distant, unexplained sounds and there are a ton of theories as to why these sounds are heard out here. They never get easier or more comforting to listen to, though! This video was taken the other night from downtown Calgary and it partially sounds like it's coming from a venue nearby, but then the pitch changes and it sounds a lot sharper and unintentional! What do you think it is?