While you were sipping pumpkin spice lattes last November, Dan Krug was brainstorming how to take his passion for climbing to (literal) new heights.

The rock climbing guide and founder of Denver Climbing Company enjoys two hobbies above most others—climbing and skydiving—so he decided to put the two together. Krug got to work, building a contraption that could hoist a three-piece climbing wall onto a lowering system, attached to a hot-air balloon. The wall folded up onto the side of the balloon for launch and landing, and climbers used a rope to rappel down and scale the wall at (insane) altitude.

In this video filmed last fall and released by multiple outlets since then (including by GoPro a few months ago), Krug took friends Max Fanning and Hank Caylor to 4,000 feet to try out the climbing wall. Krug manned the wall while Fanning and Caylor climbed, detached and skydived. “I already rock climb, I already base jump and skydive, so just jumping from the balloon or just climbing a wall is just kind of a normal day activity for me,” Krug says. “But actually being able to figure out how to suspend a climbing wall underneath [a hot air balloon] was pretty cool.”

Krug says the reactions to the video have been, understandably, mixed, ranging from ‘that’s the most awesome thing ever’ to ‘why the hell would you waste your time to do that?’

Our reaction was somewhere between a jaw-drop, shudder and jump for joy. Watch for yourself in the video below.