Here's how 7 US cities are commemorating 9/11, 25 years later

Marking the 25th anniversary of the Sept. 11, 2001 attacks, US cities are observing how four hijacked passenger planes were used by terrorists: two crashes into New York’s Twin Towers, one into the Pentagon in Arlington, Virginia, and the Flight 93 crash in a Pennsylvania field after passengers tried to retake the cockpit. Since then, the US has created more than 1,100 memorials across all 50 states. Communities are holding ceremonies that range from walks of remembrance to stair climbs. In New York City, the 9/11 Memorial & Museum at the World Trade Center includes a ceremony reading victims’ names and seven moments of silence, plus the annual “Tribute in Light.” In Arlington, the Pentagon memorial site became an affiliated National Park System area, with events at Fire Station 5. In Shanksville, Pennsylvania, observations continue at the Flight 93 crash site.