Cheering crowds lined the avenue towards Buckingham Palace for the grand finale to four days of celebrations across Britain and the Commonwealth marking Queen Elizabeth's Diamond Jubilee.

The 86-year-old monarch and her family waved to thousands of flag-waving Londoners from the palace balcony Tuesday, as Royal Air Force aircraft conducted a fly-past overhead. Prince Philip, the queen's husband of 64 years, was markedly abent, having been hospitalized Monday with a bladder infection.

Earlier in the day, Queen Elizabeth attended a solemn service of thanksgiving in St. Paul's Cathedral, joining her son and heir-to-the-throne, Prince Charles, her grandsons William and Harry, and other members of the royal family. She then led a horse-drawn carriage procession to Buckingham Palace, while military bands played and a 60-gun salute was fired.

In his thanksgiving sermon, Archbishop of Canterbury Rowan Williams said Queen Elizabeth had shown “a quality of joy in the happiness of others” during her 60 years on the throne.

In Washington, U.S. President Barack Obama issued a personal tribute to the queen, saying he hopes she will continue to “reign supreme for many years to come.” In a video posted on the White House website , Mr. Obama called her a “living witness” to the enduring “special relationship” between Britain and the United States, a bond that he said remains indispensable to their two countries and the world.

The queen will later Tuesday deliver a rare television speech to the nation.

On Monday night, Queen Elizabeth lit a symbolic torch during a moving ceremony in which Prince Charles paid a personal tribute to his mother, and led the crowd in cheers to her and his ailing father.

The crowd sang the British anthem “God Save the Queen” before Elizabeth lit the beacon and fireworks exploded over Buckingham Palace.

The London beacon was the last of 4,200 torches and bonfires lit all day Monday across Britain and the Commonwealth, starting with New Zealand and Tonga.

Elizabeth succeeded her father, King George, after his death in 1952 and was coronated the following year.

She was crowned queen of seven Commonwealth countries — the United Kingdom, Canada, Australia, New Zealand, South Africa, Pakistan and Ceylon, now known as Sri Lanka.

Along with Britain, the monarch is the head of state of 16 other nations, known as realms. Her role is purely ceremonial. She is also head of the Commonwealth, an organization that rose from the British empire. Most of its 53 member countries are former colonies.