What’s more difficult, climbing a mountain or a skyscraper? We asked a pro climber.
<img src="https://compote.slate.com/images/e87b2159-1ab6-4393-bfa3-3bb63b9def55.jpeg?crop=1560%2C1040%2Cx0%2Cy0" title="The Guy From Free Solo Is About to Climb One of the World’s Tallest Buildings Without Ropes. Is That Foolish?” />