September 11, 2001, changed the face of the US and left nearly 3,000 dead at the World Trade Center, the Pentagon and in Pennsylvania where Flight 93 was forced to crash. The attack on the World Trade Center in NYC remains the deadliest act of terror in US history.Today, 18 years after the attacks, families of the victims gathered in lower Manhattan to mourn their loved ones and, in what has become an annual tradition, read the victims' names out loud. As they read their names, family members added anecdotes about their loved ones, and read messages to them, often discussing those who carried on their legacy. The ceremony in NYC paused six times: twice for when the planes hit the Twin Towers, twice for when each tower fell, once for the attack on the Pentagon, and once more for Flight 93. On Wednesday night, the skies of New York will be lit up with the Tribute in Lights, which is two beam of light that symbolize the Twin Towers.President Donald Trump is expected to join the memorial at the Pentagon, while Vice President Mike Pence is scheduled to speak at a ceremony in memory of Flight 93 near Shanksville, Pennsylvania.Many of those killed in the attacks were first responders who attempted to save lives. “We’re at 204 [killed] in just the FDNY [Fire Department] alone, and the NYPD’s at 241. So I mean, the number of first responders that have died post-9/11 is greater,” said Bobby Eustace from the Uniformed Firefighters Association in an interview with CBS Local New York.This year's ceremony is significant, as it will be the first one to take place at the new memorial, the New York Post reported. The memorial was erected in the spring in honor of the firefighters, police officers and others who died of 9/11-related toxins after the attack. Additionally, New York Governor Andrew M. Cuomo signed a law allowing public schools to observe a moment of silence to honor the victims. "I think it's important for our state to do, and the feedback has been very positive," New York State Sen. Joseph Addabbo Jr. told WABC.