The tallest thing I ever abseiled (rappelled?) off was the QE2 Bridge in Dartford at 450 ft.
No shots available though because it was a night shift. The Dartford Crossing is a Toll Bridge so we could only close off lanes at night when it wasn't busy.
I was part of a team cleaning off and repainting the cables that suspend the road deck.
So I had to abseil off the top of one of the caissons to release a Tirfor winch.
It might not count though as the Tirfor was about 20 ft down and I climbed straight back up afterwards!

The winds were too high to continue down to the road deck 275 ft below.
Luckily each caisson had a lift in it.
![13179342704_700fce0e4a_b[1].jpg 13179342704_700fce0e4a_b[1].jpg](https://www.thetonerooms.com/data/attachments/46/46710-41eb98a6ece9704f0f2b041a937306e7.jpg?hash=QeuYpuzpcE)
On the Millennium Dome me and Sid did get the chance to climb one of the 12 yellow legs each for a jolly.
They are 100M (324 ft) tall but lean against the weight of the dome, so 95M to the ground (311 ft).
The climb was similar to yours
@Sp8ctre, with a fall arrest wire.
The tricky bit was climbing out of the cage at the top to sit on the beacon!
![construction-of-the-millennium-dome-greenwich-london-uk-P65PW7[1].jpg construction-of-the-millennium-dome-greenwich-london-uk-P65PW7[1].jpg](https://www.thetonerooms.com/data/attachments/46/46714-753b295b20b0fdead38a63e676434232.jpg?hash=dTspWyCw_e)
Here's a better vid (shorter/less Spanish).