Oct. 4, 1907:  U.S. President Theodore Roosevelt presses the conservation cause in a speech to the Deep Waterways Convention: "The conservation of natural resources is the fundamental problem. Unless we solve that problem, it will avail us little to solve all others."

Oct. 4, 1991: The Madrid Protocol is wrapped up. Signed and ratified by 27 nations, the treaty forbids mining in Antarctica at least through the year 2048. The frozen continent is believed to hold large deposits of platinum and other strategic metals.

Oct. 4, 2010: A reservoir containing millions of gallons of toxic, reddish sludge (at right) from an aluminum plant collapses, killing four and inundating several small Hungarian towns. Days later, the toxic mess reaches the Danube, Europe's second longest river, in an eerie repeat of a cyanide spill 10 years earlier.

Photo: ZUMA Press

This feature is compiled by Peter Dykstra, an MNN contributor and publisher of Environmental Health News and The Daily Climate.