Edited by Stephen Petersen, some rights reserved (CC BY-SA)
Photo Credits
- 1. (c) Howard Friedman, some rights reserved (CC BY-NC), uploaded by Howard Friedman
- 2. (c) GRID Arendal, some rights reserved (CC BY-NC-SA)
- 3. (c) Bering Land Bridge National Preserve, some rights reserved (CC BY-SA)
- 4. (c) Brian Gratwicke, some rights reserved (CC BY)
- 5. (c) gailhampshire, some rights reserved (CC BY)
