The Constitution of the United States of America is signed by 39 delegates present at the conclusion of the Constitutional Convention in Philadelphia. Supporters of the document waged a hard-won battle to win ratification by the necessary nine out of 13 U.S. states.

Beginning early on the morning of September 17, 1862, Confederate and Union troops in the Civil War clash near Maryland’s Antietam Creek in the bloodiest single day in American military history.

Early in the morning on September 17, 1868, a large band of Cheyenne and Sioux stage a surprise attack on Major George A. Forsyth and a volunteer force of 50 frontiersmen in Colorado.

On September 17, 1939, Soviet Foreign Minister Vyacheslav Molotov declares that the Polish government has ceased to exist, as the U.S.S.R. exercises the “fine print” of the Hitler-Stalin Non-aggression pact—the invasion and occupation of eastern Poland.

At the White House in Washington, D.C., Egyptian President Anwar el-Sadat and Israeli Prime Minister Menachem Begin sign the Camp David Accords, laying the groundwork for a permanent peace agreement between Egypt and Israel after three decades of hostilities. The accords were negotiated during 12 days of intensive talks at President Jimmy Carter’s Camp David retreat in the Catoctin Mountains of Maryland. The final peace agreement—the first between Israel and one of its Arab neighbors—was signed in March 1979. Sadat and Begin were jointly awarded the 1978 Nobel Peace Prize for their efforts.

On September 17, 1996, daytime talk show host Oprah Winfrey launches a television book club and announces “The Deep End of the Ocean” by Jacquelyn Mitchard as her first selection. Oprah’s Book Club quickly became a hugely influential force in the publishing world, with the popular TV host’s endorsement capable of catapulting a previously little-known book onto best-seller lists.

On September 17, 2011, hundreds of activists gather around Zuccotti Park in lower Manhattan for the first day of the Occupy Wall Street Movement—a weeks-long sit-in in New York City’s Financial District protesting income inequality and corporate corruption. While the movement failed to see any of its goals or policy proposals come to fruition, years later, Occupy Wall Street is still considered a blueprint for decentralized activism.