May 28th: On This Day in 1892 - Sierra Club is Founded

John MuirMay 28, 1892: The oldest and largest grassroots environmental organization, The Sierra Club, was founded on this day in San Francisco, California, by preservationist, John Muir.

The Mission of The Sierra Club: "To explore, enjoy, and protect the wild places of the earth; To practice and promote the responsible use of the earth's ecosystems and resources; To educate and enlist humanity to protect and restore the quality of the natural and human environment; and to use all lawful means to carry out these objectives."

May 18th: On This Day in 1980 - Mount St. Helens

May 18, 1980: Mount St. Helens, a volcano located in the Cascade Range in the state of Washington, erupted at 8:32:17 am, causing the entire weakened north face to slide away, suddenly exposing the partly molten, gas-and-steam-rich rock in the volcano to lower pressure. The rock responded by exploding a very hot mix of lava and pulverized older rock toward Spirit Lake so quickly that it avoided the avalanching north face. The explosion caused over a billion U.S. dollars in damage and resulted in 57 human deaths.