April 20, 1812: A group of up to 1,000 Luddites were driven back as they attacked a mill in Nottingham, England. The Luddites believed that the Industrial Revolution, particularly the mechanization of textile mills, would ruin the way of life for English peasants.
April 20, 1832: The Arkansas Hot Springs are established as a National Preserve, the predecessor to the National Park System.
April 20, 2003: The U.S. Environmental Protection Agency (EPA) withdraws a mine tailings site in Triumph, Idaho, from its Superfund cleanup list. The celebrity residents of the small mountain town — including Olympic skier Picabo Street and TV's "Batman," Adam West — have demanded for a decade that EPA leave the town, saying a cleanup would do more harm than good.
April 20, 2010: The Deepwater Horizon drilling platform explodes (at right) and later sinks in the Gulf of Mexico, killing 11 workers and triggering the largest oil spill in U.S. history. The wellhead, more than a mile deep, is capped in late July after multiple efforts.
Photo: ZUMA Press