On September 17, 1787, delegates to the Constitutional Convention signed the final draft of the United States Constitution at the Pennsylvania State House in Philadelphia, now known as Independence Hall. Of the 42 delegates still present, 39 signed the document, bringing four months of debate and negotiation to a close. The Constitution was then sent to the states for ratification rather than taking effect immediately.

The document established a new federal system intended to replace the Articles of Confederation, but its signing did not end the political debate surrounding it. Nine states had to ratify the Constitution before it could take effect, a threshold reached when New Hampshire ratified it on June 21, 1788. The new federal government began operating in 1789.

Howard Chandler Christy's 1940 painting depicts the signing of the U.S. Constitution at Independence Hall on September 17, 1787.

On September 17, 1944, Allied forces launched Operation Market Garden in the Netherlands during World War II. The ambitious plan combined a massive airborne assault with a ground offensive, as Allied forces sought to capture a series of bridges across the Netherlands and establish a route into Germany. Thousands of American, British and Polish airborne troops were dropped behind German lines during the opening phase of the operation.

The operation captured several key bridges but ultimately failed to secure the bridge at Arnhem for long enough to complete the planned advance. Heavy fighting continued for days, resulting in significant Allied casualties and the eventual withdrawal of British forces from Arnhem. Despite falling short of its overall objective, Operation Market Garden remains one of the largest airborne operations in military history and a major episode of the Allied campaign in northwest Europe.

Allied aircraft release paratroopers over a drop zone near Arnhem during Operation Market Garden on September 17, 1944.

On September 17, 1978, Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin signed two framework agreements at the White House following nearly two weeks of intensive negotiations at Camp David, Maryland, with U.S. President Jimmy Carter. The agreements established a framework for peace in the Middle East and for negotiating an Egyptian-Israeli peace treaty.

The documents addressed issues including Israeli withdrawal from the Sinai Peninsula and arrangements for Egyptian-Israeli relations. The agreements did not themselves constitute the final peace treaty, but they provided the framework for the treaty that Egypt and Israel signed in March 1979. The Camp David negotiations became a major episode in the history of the Arab-Israeli peace process.

U.S. President Jimmy Carter, Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin sign the Camp David agreements in September 1978.