(360' 5.6)
How good is this climb? Well, during the my single season of climbing in Boston, I did this climb no less than six times! After my first time up with Luke, it became my climb of choice when I was with new partners and beginners. Those people included Emma, Amy, Kate and Chrissy, as well as Barney, a friend visiting from Perth.
The climb takes an unlikely line up the steep Thin Air face, nearly the tallest part of Cathedral. For mine, the crux and highlight is the second pitch, a 70-foot balancy traverse (pictured) which is fortunately well-protected. (Traverses are always disconcerting for the uninitiated.) You also get juggy face climbing, a cool corner, and a tricky 5.6 move into the bargain.
I am especially fond of Thin Air because it marked the start of my taking responsibility for my climbing. I had done some multipitch climbing before, but as a second only. On this climb, I stopped following and started leading, so to speak.
Chauvin Guides have a detailed description of this climb.