- This year marks the 25th anniversary of the September 11 attacks, and on Tuesday, a moving tribute made a stop at Mount Rushmore with a significant piece of the World Trade Center. A small group of visitors watched on as a steel beam recovered from the South Tower arrived at the monument, presenting a tangible tribute to those lost in the attacks. ADVERTISEMENTThe piece is currently touring the country with the Tunnel to Towers Foundation , which was inspired by the heroic actions of off-duty firefighter Stephen Siller. It was his passion in life," his son Stephen Siller, Jr. said. So much that even when he wasn't working, he was tuned in to whatever was going on in his community.