The Duke and Duchess of Cambridge are pictured inside the 9/11 memorial museum, which opened to the public in May this year.
The attacks claimed the lives of 2,606 people in New York and 2,983 in total. The museum features photographs of the victims and various artifacts from that fateful day.
The Duke and Duchess of Cambridge laid a bouquet of flowers at the 9/11 memorial today during their visit to New York.
Kate lovingly placed the flowers down and made the sure the bow was tied around them.
The card read: "In sorrowful memory of those who died on September 11th and in admiration of the courage shown to rebuild."
Later the royal couple are due to visit the Empire State Building before hosting a ball.
It is expected to be a celebrity-studded event at the Metropolitan Museum of Art, better known as The Met.
William and Kate Duke and Duchess take courtside seats at NBA game in New York Beyonce Jay Z LeBron JamesRead the full story ›
The Duke and Duchess of Cambridge met LeBron James, aka the "King of Cleveland," after the NBA game in New York, when the basketball star posed for pictures with the royal couple.
William and Kate were presented with two Cavaliers basketball vests - one bearing the name "Cambridge" and the other a junior version for their young son, with "George" printed on the back.
The Duke and Duchess met music's golden couple Jay Z and Beyonce at the NBA game in New York tonight.
Earlier the royals were broadcast on the big screen, to cheers from the crowd.
The Duke and Duchess of Cambridge Kate and William are attending an NBA game in New York tonight, following the Prince's speech at a wildlife reception.
The couple posed for pictures with NBA legend Dikembe Mutombo and William tried to get to grips with a new basketball trick.
Prince William drew laughter from the crowds at a wildlife reception in New York tonight when he ended his speech telling the guests, "I'm off to shoot some hoops now or whatever it is you do."
The Duke and Duchess of Cambridge met Hillary Clinton and her daughter Chelsea at a reception at the British Consul General’s Residence in New York tonight.
The event, in honour of wildlife conservation charity Tusk Trust, is co-hosted by the Clinton Foundation, which works to tackle elephant poaching and the illegal ivory trade.
A young boy the Duchess of Cambridge visited at a children's centre in Harlem said: "The Princess is beautiful".
Earlier Kate had helped him make Christmas decorations at the Northside Center in Harlem.
When asked about her afterwards, he appeared coy as he revealed his crush on the Princess.
ITV News Correspondent Paul Davies has this report:
The Duchess of Cambridge has been pictured wrapping presents as she visited a children's centre in Harlem earlier today.
The Duchess also helped the youngsters, aged three and four, make Christmas decorations.
Later Kate attended a luncheon where she met British entrepreneurs working in New York.
The Duchess chats to Peter Cashmore, CEO & Founder of Mashable, one of many British entrepreneurs working in New York http://t.co/3cBnUap9Do