In a scale that hasn't been seen for around 350 years, more than 1,000 boats created a magical flotilla along the river – with the Queen, 86, at its heart. She took her place on the 210-ft. Spirit of Chartwell royal barge, which was given a makeover and bedecked with 10,000 roses, carnations, sweet peas and red charm peonies for the cruise – the centerpiece of her Diamond Jubilee.
Helping welcome her aboard were her grandson Prince William and his wife Kate.
William, 29, donned his RAF Flight Lieutenant No. 1 Dress Uniform complete with blue garter sash, while his brother Prince Harry, a Captain in the British Army, was wearing the No 1 Ceremonial dress of the Blues and Royals and Army Air Corps light blue beret. Kate wore a striking red Alexander McQueen outfit with matching hat by Sylvia Fletcher from James Lock and Co.
And it was another chance for the Queen to dress up. She wore a silver and white dress and matching coat, which had been planned the past year by Angela Kelly and made by her in-house Buckingham Palace team. Its color scheme was chosen, the palace said, in order to stand out against the regal red, gold and purple shades of the royal barge.
The Queen had been waved off from Chelsea Pier with her son and heir Prince Charles (in his Royal Navy Admiral's ceremonial day dress uniform), and his wife Camilla (in an Anna Valentine dress and Philip Treacy hat,) who had joined her for the three-quarter mile journey aboard the Britannia launch that took them to the royal barge.
Braving the blustery, often showery weather, enthusiastic crowds numbering an estimated one million people lined the river route – a similar number reported to have been on the streets of London for the wedding of William and Kate last year.
Matt Dunham-Pool / AP
The Order of the BoatsThe Spirit of Chartwell moved off shortly after sea cadets, showing the many flags of the Commonwealth, and a group of rowing boats had passed her. One rowboat was being partly manned by TV presenter Ben Fogle, who said, "It's an unbelievable feeling down here … hip,hip, hooray!"
Not far behind was the paddle steamer the Elizabethan with Kate's parents, Michael and Carole Middleton, as well as her sister Pippa and brother James, waving across the river.
Slightly behind the Chartwell was Havengore with Prince Andrew and his daughters Princess Beatrice and Princess Eugenie, on board, along with the Earl and Countess of Wessex and some of the Queen's cousins.
The Queen's daughter Princess Anne and her husband Vice-Admiral Sir Timothy Laurence, were on the Trinity House No. 1 Boat.
The flotilla is set to take three hours to wind along the seven miles of the river set aside for the pageant. They include rowing boats, veterans from the World War Two battle at Dunkirk, politicians and some British celebrities. The London Philharmonic Orchestra played "Singing in the Rain" as the boats made their slow trip down the famous river.
Meanwhile, street parties were taking place across Britain, with local authorities reporting around 10,000 applications to close streets – almost double those that took place in April last year for the royal wedding. And one had some special royal visitors: Prince Charles and the Duchess of Cornwall nipped up to Piccadilly, not far from their home at Clarence House, and sat down with 500 revelers at a table decked with red, white and blue.
"We have to get going so we can catch the boat – can't be late!" Camilla said as they dashed off to the pageant.