Alex Hyde / Low angle view of Porcelain fungus (Oudemansiella mucida) growing on a dead Beech tree (Fagus sylvatica). Plitvice Lakes National Park, Croatia. November.

Hiroya Minakuchi / Jellyfish (Spirocodon saltator), Japan

Edwin Giesbers / Reticulated glass frog (Hyalinobatrachium valerioi) captive, occurs in Colombia, Costa Rica, Ecuador, and Panama

Pete Oxford / Glass Frog (Hyalinobatrachium aureoguttatum) underside showing internal organs, native to South America

Pete Oxford / Glass Frog (Hyalinobatrachium aureoguttatum) underside showing internal organs, native to South America

Pete Oxford / Glass Frog (Hyalinobatrachium aureoguttatum) underside showing internal organs, native to South America

Franco Banfi / Freshwater jellyfish (Craspedacusta sowerbii) Lake Lugano, Ticino, Switzerland. August. Invasive species.

Solvin Zankl / Portuguese man-of-war (Physalia physalis) colony, underwater Sargasso Sea, Bermuda

Alex Hyde / Spider (Tegenaria sp.) in dew-covered web in limestone cave, Plitvice Lakes National Park, Croatia. January.

Floris van Breugel / Flawless crystalline ice, produced through millennia of glacial pressure, floating on Lago Grey, Torres del Paine National Park, Chile, June 2014.

Olga Kamenskaya / Ice formations in snow on Lake Baikal, Siberia, Russia, March 2007.

Olga Kamenskaya / Clear pane of ice on Lake Baikal, Siberia, Russia, March 2007.