While most visitors to Yosemite National Park come in the summer months, winter is a magical time of year in Yosemite Valley. The majesty and solitude of its snow-capped cliffs and frozen lakes fascinated Ansel Adams, who returned again and again over the decades to make hundreds of photographs of the rugged landscape in winter.

Adams, Ansel (Feb. 20 1902 — Apr. 22, 1984), photographer and environmentalist, was born in San Francisco, California, the son of Charles Hitchcock Adams, a businessman, and Olive Bray. The grandson of a wealthy timber baron, Adams grew up in a house set amid the sand dunes of the Golden Gate.

As we celebrate Earth Day this year we are reminded of the diligence required to affect change. Today the environment continues to be attacked and the clock is being turned back on progress on many fronts. Ansel Adams spent decades in the battle to protect our environment. At his core, his activism was driven by his love of the environment and his humanity. The tumultuous 1968 Democratic National Convention included a visit from Ansel. Ever the outspoken environmentalist, Ansel gave a presentation to the DNC Platform Committee. His remarks, reprinted here , were prescient and are unfortunately more apt today than 50 years ago.