The terraces of Mammoth Hot Springs in NW Yellowstone consist of shallow pools with ledges draped with ribbons of travertine. Rapid deposition encroaches on nearby forests and can produce changes visible within a period of weeks.

Photo by Lee Siebert, 1968 (Smithsonian Institution).

This image is made available under the Public Domain Dedication CC0 license, but proper attribution is appreciated.

Yellowstone