Standing a top a mesa and watching a B-52 fly through a canyon is astounding.
I can only imagine.
You oughta try it from the Buff's perspective. I did it in '73 as an ATC observer in the IP seat, flying out of Kincheloe to La Junta, CO for low level training. VERY senior crew, (I was accorded VIP treatment) consisted of 4 Majors with combat experience.
Screaming through canyons at 360 kts indicated, pilot's blast screen down - flying 200' terrain avoidance, watching sheep scatter on hillsides.
The mountain waves made the ride tremendously rough, like hitting a row of fence posts in a car at 100 mph. So rough at times you would momentarily lose visual acuity (could not read instruments), but the crew had been trained to deal with that.
This was in the days of SAC - it was a nuclear certified crew - and was by FAR the most professional operation I have ever seen.
I've been lucky enough to see and do some cool stuff, but that ride was certainly a highlight. And to add icing on the cake, after the run we went to altitude & got our scoring, then the Pilot says "Damn, pretty good (it actually was an extremely high score I learned later), let's see if we can beat it".
The beating those airframes take is astounding, it's simply unbelievable they could have such long lifespans.