Another rock climber writes in:
Free-soloing is something a fair number of climbers do. To see it done by someone who’s the best in the world at it, like Alex Honnold, is certainly striking. It’s obvious that climbing fingernail-sized holds on an overhanging wall is beyond the ability of most people, but then you add “no rope” and jaws drop.
But really, free-soloing is just the same as what you do when hiking, just steeper. Fred Beckey, ancient Pacific Northwest climber and notorious sandbagger, rates the difficulty of many mountain climbs in the North Cascades of Washington as “class 4,” which is generally defined as “unroped climbing where a fall will kill you.” That’s free-soloing. None of those climbs looks anything like Honnold’s video, but people achieve the same freedom of movement, exertion, danger, and focus, in an amazing natural environment.
The above video is a good example of perilous class 4 scrambling. Says the climber in that video, “The scary stuff starts at about the 6 minute mark, when I get up on the knife-edged ridge.” Here’s a good video tutorial of the differences of class 1 through class 4.