At the same time, a mysterious monument is found at the north pole of Pluto, tying up with a passing mention in the engineer's diary.

In the final narrative, the great-grandson of the archaeologist visits the monument on Pluto, a scaled-up version of Stonehenge carved in ice.

The first part of this novel was originally published as the novella To Leave a Mark in the November 1982 issue of The Magazine of Fantasy & Science Fiction.

[1] The third part of Icehenge was originally published as the novella On the North Pole of Pluto in 1980 in the anthology Orbit 18 edited by Damon Knight.

[2] Robinson gave the novella in rough form to Ursula K. Le Guin to read and edit while he was enrolled in her writing workshop at UCSD in the spring of 1977.