The 9/11 National Memorial Trail opened yesterday at the Flight 93 Memorial in Somerset County, along with two other nearby national parks. Ultimately the trail will be 1500 miles long connecting the Flight 93 Memorial in Somerset County to memorials at the Pentagon and the Twin Towers in New York. The trail will eventually go thru 18 national parks. Yesterday, three of those 18 were complete. The completed sites are the Flight 93 Memorial, Johnstown Flood Memorial and the Allegheny Portage National Historic site. The trail, at the Flight 93 National Memorial is in the area of Memorial Plaza.