Second paragraph of third section:

She climbed down and followed the tunnel along the outside. After the corkscrew there was another straight horizontal section, longer this time, then more turns, to left and right and up and down, and then something different. A larger chamber, from which the “main” tunnel continued a little offset to the right, but there was also another branch going off sharply left.

A stunning short story about a woman assassin in a Stalin-era prison camp, and the way out offered by the legacy of the Tunguska meteorite. Blew my mind. You can get it here.

This was the shortest unread book that I acquired in 2020 (one of many in the Hugo Packet), and also the sf book that had lingered longest unread on my virtual shelves. Next on those lists respectively are Would She Be Gone, by Melanie Harding-Shaw, and The Impossible Contract, by K. A. Doore.