Updated 10:07 a.m. ET, June 3, 2012.
(AP) LONDON - More than 1,000 boats will sail down the River Thames on Sunday in a flotilla tribute to Queen Elizabeth II's 60 years on the throne that organizers are calling the biggest pageant on the river for 350 years.
Despite cool, drizzly weather, hundreds of thousands of people lined the riverbanks between Hammersmith and Tower Bridge in London, feting the British monarch whose longevity has given her the status of the nation's favorite grandmother.
Spectators cheered the queen and members of her family as they arrived for their trip aboard a flower-bedecked royal barge, accompanied by skiffs, barges, narrow boats, motor launches, row boats and sailing vessels from around the world.
The queen wore a silver and white dress and matching coat, embroidered with gold, silver and ivory spots and embellished with Swarovski crystals to evoke the river, as she and her husband Prince Philip were ferried by motor launch to the barge Spirit of Chartwell
Prince William and his wife the Duchess of Cambridge - he in his Royal Air Force uniform, she in a red Alexander McQueen dress - and Prince Harry were among senior royals accompanying the queen on the river trip.
Hundreds of people ignored the persistent rain and camped out overnight to secure prime riverside spots. Crowds swelled into the thousands Sunday, with revelers in hats, flags, leggings and rain ponchos adorned with the Union flag mixing with burger and cotton candy vendors along the 7-mile (11-kilometer) route.
"It would have been wonderful if it had been sunny like last Sunday but we have come prepared," said 57-year-old Christine Steele. "We have got blankets, brollies (umbrellas), flags and bunting. We even got our glittery Union Jack hats and wigs, and the Champagne is on ice."
The spectacle is a tribute to Britain's past - monarchs used the river as their main highway for centuries, and naval power built the island nation's once-great empire - as well as to its abiding love of boats and the sea.
River processions were once common in London. The last comparable royal pageant was held for King Charles II in 1662, when diarist Samuel Pepys recorded boats so numerous he could "see no water."