Jeff Foott / Waterfall, Grand Staircase-Escalante National Monument, Utah

Yva Momatiuk & John Eastcott / Waterfall and peak, Fitzroy Massif, Los Glaciares National Park, Patagonia, Argentina

Yva Momatiuk & John Eastcott / Waterfall and peak, Fitzroy Massif, Los Glaciares National Park, Patagonia, Argentina

Ingo Arndt / Christmas Island Red Crab (Gecarcoidea natalis) blurred view of vast number of individuals moving along their annual migration route, Christmas Island, Indian Ocean, Australian Territory

Ingo Arndt / Flock of Rooks (Corvus frugilegus) roosting in tree at dusk, Hessen, Germany, Europe

Hiroya Minakuchi / Japanese Firefly (Luciola cruciata) group flying along river at night, Shikoku, Japan

Pete Oxford / Kaieteur Falls, Potaro River, Kaieteur National Park, Guyana

Chien Lee / Stream in lowland rainforest, Masoala National Park, Antsiranana, Madagascar

Matthias Breiter / Trees in autumn along river, Sand River, Agawa Bay, Ontario, Canada

Matthias Breiter / Creek flowing into lake in temperate rainforest, Lake Crescent, Olympic National Park, Washington

Matthias Breiter / Waterfall and creek in temperate rainforest, Merriman Falls, Olympic National Park, Washington

Jack Dykinga / Lightning storm with rainbow over Saguaro cactus (Carnegiea gigantea) Avra Valley, Saguaro National Park, Tucson Mountains, Arizona, USA, August 2015. Long exposure with lightning trigger.