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Went pretty viral in various news articles around the World.
The drone pilot has apparently had some good offers from all sorts of places (movie production in particular) since this and another couple of their vids came to light.
Very simply little cinewhoop or similar, get into tight spots relatively safely.
They said that was one take, and probably was, but who knows how many takes they did before they didn't touch and crash as they often do.
Virtually indestructible of these little drones means you can do this and not have too much risk or injury or damage to drone / property.
edit typo