World Listening Day 2017 had the theme Listening To The Ground in honour of Pauline Oliveros.
“Sometimes we walk on the ground, sometimes on sidewalks or asphalt, or other surfaces. Can we find ground to walk on and can we listen for the sound or sounds of ground? Are we losing ground? Can we find new ground by listening for it?”—Pauline Oliveros (1932-2016)
Here is an hour of experimental listening (to the ground).