A collection of repeat photography of glaciers from the National Snow and Ice Data Center (NSIDC). The photos are taken years apart at or near the same location, and at the same time of year. These images illustrate how dramatically glacier positions can change even over a relatively short period in geological time: 60 to 100 years. Background essay and discussion questions are included.

This NASA video provides a nice overview of Earth's water cycle from the perspective of looking at Earth from space.