Bryan and Cherry Alexander / Two people dismantling their tent at Weincke Island, Antarctica.

Bryan and Cherry Alexander / Expedition cruise ship "Grigoriy Mikheev" encounters a Polar bear (Ursus maritimus) on the shifting pack ice west of Spitsbergen, Svalbard, Norway, June.

Bryan and Cherry Alexander / Russian icebreaker "Kapitan Khlebnikov" parked in the sea ice with tourists walking close by. Antarctica, October 2006.

Bryan and Cherry Alexander / Russian Mi-2 helicopter by the safety tents at Snow Hill Island. Antarctica, October 2006.

Bryan and Cherry Alexander / Yellow jacketed tourists visiting the Emperor Penguin (Aptenodytes forsteri) colony at Snow Hill Island Antarctica, October 2006.

Bryan and Cherry Alexander / Aerial view of safety tent and passengers walking to the Emperor Penguin Colony at Snow Hill Island. Antarctica, October 2006.

Bryan and Cherry Alexander / Woman using the field toilet at Mount Vinson Base Camp. Vinson Massif, Antarctica, January 2006.

Juergen Freund / Divers surface in Chanderlier cave, Palau, Micronesia

Onne van der Wal / Cable car ride to the top of Table Mountain with a vast view across Cape Town, South Africa.

Roberto Rinaldi / A diver immersed in a flooded cave in Perito Moreno glacier, securing a rope that will enable him to find his way back, Los Glaciares National Park, Patagonia, Argentina

Roberto Rinaldi / Two divers starting their dive inside a crevasse of the Perito Moreno glacier, Los Glaciares National Park, Patagonia, Argentina

Roberto Rinaldi / A diver ready to dive inside a crevasse full of water on the surface of Perito Moreno glacier, Los Glaciares National Park, Patagonia, Argentina