Franco Banfi / Climbers on ice wall, Mendenhall Glacier, near Juneau, Alaska, North Pacific Ocean.

Ole Jorgen Liodden / Ice climber on ice cliff, Hallingdal, Norway, March 2005.

Ole Jorgen Liodden / Ice climber on ice cliff, Hallingdal, Norway, March 2005.

Ole Jorgen Liodden / Ice climber on ice cliff, Hallingdal, Norway, March 2005.

Nigel Bean / Ivy (Hedera helix) leaves edged with hoar frost, Somerset Levels, UK, December

Nigel Bean / Close up of Ivy (Hedera helix) leaves edged with hoar frost, Somerset Levels, UK, December

Nigel Bean / Ivy (Hedera helix) leaves edged with hoar frost, Somerset Levels, UK, December

Nigel Bean / Ivy (Hedera helix) leaves edged with hoar frost, Somerset Levels, UK, December

Colin Monteath / Climbers cross open crevasses on Fortuna Glacier retracing Sir Ernest Shackleton's epic crossing of South Georgia in 1916

Doug Allan / Climbers on the Khumbu icefall, Mount Everest, Himalayas, Nepal

Leo & Mandy Dickinson / Sherpa on ladder at Khumbu icefall. Mt. Everest, Himylayas, Nepal

Leo & Mandy Dickinson / Climbers Reinhold Messner and Peter Habeller dwarfed by Khumbu icefall block. Mt. Everest, Himylayas, Nepal