Queen Elizabeth paid her first visit to the site of the Sept. 11, 2001 terrorist attacks in New York Tuesday to honour the thousands of people, including 67 Britons, who died that day.

On a scorching day that reached 38 degrees Celsius, the Queen laid a wreath of peonies, roses and lilies at what was once the foot of the World Trade Center's south tower. The Queen, who was accompanied by Prince Philip, then met with emergency services workers who responded to the attacks, as well as family members of victims.

The royal couple also visited the British Garden of Remembrance, a memorial to the Britons who died on 9-11.

Earlier Tuesday afternoon, the Queen addressed the UN General Assembly for the first time in more than 50 years, praising the world body for its achievements but warning that member states must work together if they are to tackle challenges like terrorism and climate change.

After a packed nine-day trip to Canada, the Queen and Prince Philip landed in New York for a rare visit to the United States.

Upon landing in the city, the royal couple was immediately whisked to UN headquarters, where they were greeted by UN Secretary General Ban Ki-moon and General Assembly President Ali Abdessalam Treki and their wives.

After a brief welcoming address by Ban, who thanked the Queen for her appearance at the General Assembly, the Queen briefly addressed delegates.

"Many important things have not changed (since 1957)," the Queen said. "The aims and values which have inspired the United Nations charter endure: to promote international peace, security and justice; to relieve and remove the blight of hunger, poverty and disease; and to protect the rights and liberties of every citizen. The achievements of the United Nations are remarkable."

After noting that overseas UN missions have grown from three in 1957 to 26 in the present day, Her Majesty praised the organization for its efforts to help reduce conflict, offer humanitarian assistance to people affected by natural disasters and combat poverty. "But so much remains to be done," she said.

"For over six decades the United Nations has helped to shape the international response to global dangers. The challenge now is to continue to show this clear leadership by not losing sight of your ongoing work to secure the security, the safety and the liberty of our fellow human beings," the Queen said.

"In my lifetime, the UN has moved from being a high-minded aspiration to being a real force of common good. That of itself has been a signal achievement. But we are not gathered here to reminisce. In tomorrow's world we must all work together as hard as ever if we are truly to be United Nations."

After her speech, the Queen was scheduled to tour the World Trade Center site and lay a wreath in honour of the thousands of people who died in the Sept. 11, 2001 terrorist attacks.

Canadian visit wraps up

Before the royal couple travelled to New York, they wrapped up their nine-day Canadian tour at the Ontario legislature, where a large crowd gathered to say goodbye.

The last few hours of Queen Elizabeth's Canadian itinerary were as busy as her first. The 84-year-old presented citizenship awards at the Ontario legislature Tuesday morning, before unveiling a plaque commemorating the 150th anniversary of the dedication of Queen's Park.

It was, in fact, the Queen's own great-grandfather, the future King Edward VII, who first dedicated the park, which was named for his mother, Queen Victoria.

The Royal Couple were then given a 21-gun salute send-off on the legislature lawn, before heading to Pearson International Airport.

Richard Berthelsen, a former Royal tour organizer, said the Queen kept up an "absolutely remarkable" pace over her Canadian tour that took her through parts of Nova Scotia, Ontario and Manitoba.

As she was greeted by large crowds of admirers, both old and young at every stop throughout her Canadian sojourn, Berthelsen said there was a sense that the Queen's 22nd visit to Canada was a particularly special occasion.

"So many parents and grandparents have been taking their children and grandchildren to see the Queen, because I think there is a sense that this is a really important historical moment as we're seeing the sunset years of the Queen's reign -- and it has been a remarkable reign," Berthelsen told CTV's Canada AM during an interview in Toronto on Tuesday morning.

From the moment the Queen arrived in Canada on June 28, she was engaged in official Royal duties. Within hours of landing in Halifax, she had visited the city's Garrison Grounds, met with Prime Minister Stephen Harper and Gov. Gen. Michaelle Jean, attended a luncheon at CFB Halifax and inspected a flotilla of international ships.

After visiting Nova Scotia, she travelled to Ottawa where she attended Canada Day festivities and told Canadians how proud she was of how the country has "grown and matured while remaining true to its history, its distinctive character and its values." The Queen also unveiled a statue of Oscar Peterson, the famed late Canadian pianist who performed for the Royal Couple when they toured Canada in 2002.

Next, the Queen travelled to Winnipeg for a whirlwind six-hour visit in which she signed a letter for a time capsule, visited a soon-to-be-unveiled international airport and unveiled a cornerstone at the Canadian Museum for Human Rights.

The final portion of the Queen's Canadian visit took place in Ontario, where the Queen attended a church service in Toronto, watched the Queen's Plate horse race, and toured the Research in Motion headquarters in Waterloo, Ont., among other events squeezed into the final three days of her tour.

Royal watcher Richard Fitzwilliams said the latest Royal visit went "extraordinarily well."

Speaking to CTV News Channel from London, Fitzwilliams said he expects the Queen will again return to Canada if she is able to do so, as it has been a favourite destination of hers for decades.

During a 1959 visit to the United States, the much younger Queen met with the late president Dwight D. Eisenhower.

"When asked at the end where she was going, she replied she was going home, which she meant to Canada," Fitzwilliams said of the Queen's exchange with Eisenhower.

With files from The Associated Press and The Canadian Press