Few things are as inspirational as people who put their lives on the line for a cause greater than themselves. For National Geographic photojournalist Paul Nicklen, that includes diving beneath sea ice, swimming with leopard seals off Antarctica and trekking across miles of stark Arctic wilderness in -40F temperatures.
His cause? Convincing all of us to care for this wild and precious planet.
Enjoy the inspiration! And when you're done, please share the link with two other friends, neighbors or colleagues. You, they - and the Earth - will be glad you did.