PS, the crevasses you see can give an adrenaline hit; the ones you don't see, a king-hit :oo:
Mallory dropped into one during his 2nd expedition to Everest I think it was. Luckily his ice axe was underneath him and wedged itself between the walls, holding him. He managed to scrape a ramp and crawl out.
When they knew dangers were there they'd rope up, but even the heavy hemp rope at the time would fail with a body weight drop of 7 or 8 metres.
Much later Meissner, the first climber to ascend Everest without oxygen, also dropped into a crevasse and managed to haul himself out.