Americans are marking 24 years since the Sept. 11, 2001, attacks with solemn ceremonies, volunteer work and other tributes honoring the victims. Many loved ones of the nearly 3,000 people killed joined dignitaries and politicians at commemorations Thursday in New York,. Others attended ceremonies at the Pentagon and in Shanksville, Pennsylvania. In New York, Joann Doria Cross, the wife of a firefighter who died on 9/11 said visiting the site now makes her feel good. Her daughter Laura Cross said she finds visiting the site peaceful and calm. She said President Donald Trump's plans to have the federal government take control of the site would be a good thing. "I think that I would like it to be a national park, because I think the nation needs to come together. " The remembrances are being held during a time of increased political tensions. The 9/11 anniversary, often promoted as a day of national unity, comes a day after conservative activist Charlie Kirk was shot and killed while speaking at a college in Utah.