Flight 93 Memorial
Somerset County, PA
On September 11, 2001, two airliners were hijacked soon after departure from Boston and flown into the World Trade Center in New York City. A third plane from Washington, DC was hijacked and flown into the Pentagon.
A fourth plane, United Airlines flight 93, (a Boeing 757 departing from Newark, NJ which had been delayed 45 minutes) changed course near Cleveland, OH and appeared to be heading toward Washington, DC. Through cellphone calls home, the 33 passengers and seven crew heard about the NYC and DC attacks and, apparently, attempted to regain control of the craft. The plane plowed into a reclaimed strip mine in Somerset County, PA at around 500 miles an hour, completely demolishing the vehicle and killing all on board.
A makeshift memorial was built a few hundred feet from the filled-in crash crater with a chain-link fence for flowers and commemorative items. On September 24, 2002, the Flight 93 National Memorial Act (P.L. 107-226) was passed by Congress and signed into law, creating an official memorial at this site.
While on a children's theatre tour at the nearby Mountain Playhouse in 2002 and 2006, I had some free time to visit the site. Although there were some improvements and additions over the intervening four years, the memorial remained a fairly primitive but striking commemorative destination.
Official Park Service site