1,999 ft
Once the guy gets exposed and is climbing up pegs ... um wow. This would take a lot of mental training before I could do something like this.
The factor of safety in these towers must be pretty high, but if I was up there and the wind starting picking up and the tower began swaying... that's where I'd begin losing my mind!
When the guy got to the top I was thinking, "I hope he doesn't drop that light bulb"