Graham Eaton / Underwater view of a rapidly flowing mountain stream, Snowdonia NP, Gwynedd, Wales, UK, November

Graham Eaton / Underwater view of a mountain lake with frozen surface, Llyn Idwal, Snowdonia NP, Gwynedd, Wales, UK, December

Graham Eaton / Underneath the ice of Llyn Dinas lake, Snowdonia NP, Wales, December

SINCLAIR STAMMERS / Coastline by Culver cliff, Isle of Wight. In the Early Cretaceous era Wealden clays was a tropical lakebed. Fossilized dinosaur footprints can now be found amongst loose boulders at the toe of the cli...