Alan Williams / Beaver Bridge over River Conwy, near Betws-y-Coed, Snowdonia National Park, North Wales, UK, September 2018

Graham Eaton / An underwater view of a woodland stream, River Glaslyn, Snowdonia NP, Gwynedd, Wales, UK, May

Graham Eaton / A low angle view of a waterfall, from within a mountain stream, Ogwen Cottage, Snowdonia NP, Gwynedd, Wales, UK, February

Graham Eaton / Underwater landscape within a mountain stream, showing water turbulence, Snowdonia NP, Gwynedd, Wales, UK, December

Graham Eaton / View looking up a waterfall from within a stream, Snowdonia NP, Gwynedd Wales, UK, December

Graham Eaton / A split-level image of a mountain stream, in autumn, with water droplets on lens, Nant Ffrancon Valley, Snowdonia NP, Gwynedd, Wales, UK, October

Graham Eaton / View towards Arenig Fach over open moorland, with stormy sky and dark clouds. Snowdonia NP, Gwynedd, Wales, UK, October

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

Graham Eaton / View of frozen Llynnau Mymbyr, a mountain lake, with fog partly revealing a mountain ridge, Snowdonia NP, Gwynedd, Wales, UK, December

Graham Eaton / A split-level view through a small waterfall, Llanberis, Snowdonia NP, Gwynedd, Wales, UK, July

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

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