Thanks to Biz, I recently found out about a sculpture at Stanford by Andy Goldsworthy. Antonia and I were traipsing around campus this afternoon so we went out to look for it. It's right by the Cantor Arts Center, but easy to miss because it's sunk into the ground, though you can see it if you go up the steps to the museum and then turn around.
The wall is just a few feet high, and it's made of stones from Stanford buildings that were damaged in the 1906 and 1989 earthquakes. The ends trail off into the ground as though the whole wall were growing out of the earth. It's only a few years old now, but the idea I think is to gradually let all the plants come back around it naturally, so it looks even more like an integral part of the land. Already a lot of the stones have moss or other small plants growing in their nooks. There's even a door for the fairies to come through. We walked all the way along it on one side of the wall, then back on the other, tracing every curve as though walking a labyrinth.
I also watched Rivers and Tides a few days ago, which is a documentary about Andy Goldsworthy. I am thoroughly hooked on his art now. There's something very profound and beautiful about how it all feels so natural, and yet is so clearly art as well. Really wonderful.