American alligatorJune 4, 1987:  After 20 years of protection as an endangered species, the American Alligator is removed from the Endangered Species List.    Decades of overhunting, combined with habitat loss, had imperiled the gators.

June 4, 1989: Sparks from two passing trains are said to ignite fumes from a leaking natural gas pipeline in the Ural Mountains of the central Soviet Union, killing more than 500 on the trains. Many of the victims are schoolchildren headed to camp near the Black Sea.

June 4, 1992: Nations begin to sign the U.N. Framework Convention on Climate Change (UNFCCC), the first serious global effort at a concerted response to a warming earth.

Photo: National Parks Service

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