Commemorate the Tragedy's 20th Anniversary at the 9/11 Memorial & Museum

Elsewhere in the museum, you'll see the Survivors’ Stairs, used as an escape route by hundreds on 9/11, and the original steel column bases that anchored the Twin Towers, looming like ghosts out of the wreckage. In all, the museum has more than 14,000 artifacts either salvaged from the attacks or donated by the families of the victims, first responders who survived, or relief workers who manned Ground Zero post-9/11.

See a red bandanna worn by Welles Remy Crowther, a 24-year-old equities trader-turned-hero in the South Tower. At age 16, he became a volunteer firefighter in his hometown of Upper Nyack, New York, and he used that training on 9/11 to guide survivors to the only viable staircase for escaping. To protect himself from the smoke, he covered his nose and mouth with the bandanna. Sadly, he ultimately died in the attack.

Read some of the heartfelt messages scribbled by recovery workers on the yellow hard hat worn by Salvation Army volunteer Debora Jackson, a Brooklyn resident who felt a calling to help and manned relief tents around Ground Zero for several months after 9/11. “To one of the best women I've ever met,” wrote one grateful worker.

Another must-see exhibit: “In the Hunt for Bin Laden,” which runs through January, details the extraordinary steps the U.S. government took to find the man considered the mastermind behind the attacks.

Sean Pavone / Alamy Stock Photo

20th Anniversary activities

To observe the milestone anniversary, family members of the victims will gather on the memorial plaza at 8:30 a.m. to begin the annual ritual of reading aloud the names of those who lost their lives in the 9/11 attacks, as well as in the 1993 bombing. As the names are read, moments of silence will be observed six times, corresponding to the times when the two towers were struck, when they fell, when the attack on the Pentagon occurred, and when Flight 93 crashed in Pennsylvania. Houses of worship will be encouraged to toll their bells at 8:46 a.m., when the first plane struck.

Although the ceremony is restricted to families of the victims, everyone in the vicinity will be able to view the annual “Tribute in Light.” In Lower Manhattan, near the site of the memorial, two beams of light representing the Twin Towers will soar up to four miles into the sky and be visible from as far away as 60 miles. Buildings throughout the city will light up their facades and rooftops in sky blue as well.