Glaciers

When snow accumulates over many years, it compacts into dense ice. Glaciers form as this ice slowly but steadily slides downhill.

Some ten percent of the land on Earth is covered by year-round ice. Most of that is the polar ice sheets of remote Antarctica, a next-to-impossible destination for most people, and in Greenland, which is also far off the beaten path. There are other places, either at high latitudes, high elevations, or both, where you can see remnants of the massive ice sheets that covered much of the earth just a few thousand years ago. As climate change advances, glaciers around the world are in retreat, and many of them could disappear in the lifetime of anyone reading this.