A Muslim man standing on a sand dune at sunset wearing a traditional dishdasha and masar. Escarpment A scuba diver with a

A scuba diver with a digital video camera explores a tropical reef

Pressure ridges in a glacier build up around an island in the Greenland Ice Sheet

An aggregation of bright red and yellow Morpho telemachus caterpillars gathered on a leaf

Two large Adelie Penguin chicks fight using their razor-sharp beaks

Sun rays highlight a dead tree trunk at sunset below a forest canopy

A Muslim man standing on a sand dune at sunset wearing a traditional dishdasha and masar. Escarpment A scuba diver with aA Muslim man standing on a sand dune at sunset wearing a traditional dishdasha and masar. Wahiba Sands, Ramlat al Wahiba, Sharqiya Sands, Sultanate of Oman.