Seepweed covered mudflats, Seongmodo, Ganghwado.
Rather neat - tide rapidly coming in and flooding a tidal flat, Kenya
MUDFLATS: Superb Fossil locales of the Past and the Future?
The photo included with this post is from the Delta of the Colorado River as it enters the Sea of Cortez (also known as the Sea of California). It shows a rather special example of a mudflat environment.
(Source: facebook.com)