Back when I was a teenager, there was a cave in the Rockies (Bragg Creek Ice Caves) that I explored with my school friends.
After climbing up a 1000' scree slope that deters casual tourists, the first cavern is huge, and many people check it out. There is an ice flow on the floor that retreats a bit in summer, but is always there towards the back, a couple of hundred feet in. There is daylight all the way to the back of the first cavern.
The access to the second cavern is a tunnel that starts at chest height on a wall at the back of the first cavern, and that you have to crawl on elbows and toes. Depending on the ice, some years it is not accessible at all. The tunnel is, I think, about 50 feet long. The second cavern is a palace of ice crystals on the walls. There is no light except from your flashlights.
Few people make it to the third cavern, which is accessed by a 30' corkscrew vertical tunnel from the second cavern. THe cavern's floor is a slab tilted at about a 30 degree angle.
The temperature in the cave is a uniform 0C (32F) all year. There is a wind that blows constantly from the third cavern, through the passages, and out the main entrance.
Like I said, we were kids, young and foolish. We were at least sensible enough to bring spare flashlights. I doubt if I would do the same kind of expedition today!
https://braggcreek.ca/kananaskis/icecave/
