Eyes of world on spectacular Thames royal pageant Gloriana leads the way Queen on the water Heading to The Gloriana William, Kate and Harry arrive Queen celebrates 60 years on the throne Row boats sit on the Thames Rain, rain, go away... Celebrating the queen's milestone Dressing up for the occasion Anti-royalist protests Royal guests at street party Epsom Derby day Tens of thousands celebrate along the banks of the Thames Royal family led flotilla of a thousand boats up river to Tower Bridge London (CNN) -- The Thames became a sea of red, white and blue Sunday, as tens of thousands celebrated the diamond jubilee of Queen Elizabeth II -- so perhaps it was only fitting that alongside all the flags, another great British tradition was very much in evidence: Gray skies and rain. Some 20,000 people took to the water aboard 1,000 vessels for a river pageant featuring dragon boats, a floating belfry and the royal barge. The event -- inspired by regal riverside celebrations of the past -- was the largest such celebration on the Thames for hundreds of years. Around a million people were expected to line the route to cheer on the queen, at the head of a seven-mile long flotilla. But bad weather meant a planned fly-past was canceled. Follow CNN's live blog Isabella Hales and her family staked out their claim to a spot near Tower Bridge -- where the festivities reached a climax on Sunday evening. "It's cold, but I don't mind," the 10 year old, wearing a cardboard Duchess of Cambridge mask that was rapidly dissolving in the drizzle, told CNN. iReporters celebrate Queen Elizabeth II After gathering upriver in west London, the flotilla made its way from Battersea Bridge to Tower Bridge, passing through the heart of Britain's capital city over the course of several hours. At the front were 300 man-powered boats, with thousands of volunteers propelling them down river, flags and streamers fluttering around them. A barge carrying the eight Royal Jubilee Bells -- the largest of which, at nearly half a ton, is named for the monarch -- led the way, with peals of bells ringing out from church towers along the river. Next came passenger boats, pleasure boats, historic wooden vessels -- the oldest built in 1740 -- and boats carrying members of the armed forces, police and fire services. The biggest cheers were reserved for the present queen, who was carried aboard a specially-converted royal barge, opulently draped in red and gold. Sailing boats that were too tall to pass under the 14 bridges along the river pageant route lined the river from London Bridge to Wapping, in the east, creating an avenue of sails set against the Tower of London and the city's financial center. The queen disembarked at Tower Bridge and looked on as the remainder of the river pageant passed by in a riot of color and noise. Excitement grew as a gun salute rang out from the Tower of London. Nearby, those not lucky enough to get a riverside spot before the area was locked down, watched the pageant on a big screen. Cheers, whistles and the odd chorus of "God Save the Queen" rang out, and the crowd stayed jolly despite the rain. Helen McKee, from Kent, said she bought her family along to enjoy a once-in-a-lifetime spectacle. We're never going to see this sort of thing again. I've got a little boy and I thought it was important for him to see it. I still remember the Silver Jubilee in 1977. It's a great atmosphere here, everyone is so friendly. To Jamie Newell, from London, events on the river were just a forerunner of the main attraction of the day - the after party he was planning at home. Newell, decked out from head to toe in Union flags, and sporting red, white and blue contact lenses, said simply: "I love the queen." Not everyone was of the same opinion. In a street behind the London Assembly building, scores of pro-republican campaigners had gathered, waving placards reading: "Make monarchy history" and "Don't jubilee-ve it" and chanting "Monarchy out, republic in." Today though, they seemed resigned to the fact that they were well and truly in the minority. As the queen's barge approached and Tower Bridge lifted in salute, red white and blue streamers were tossed from the crowd. And then, as if on cue, the heavens opened, rain lashing those gathered on the riverbanks below. Hoods and umbrellas went up, coats and ponchos went on, quickly followed by shouts of "brolleys down" from those behind. Some of those who had gathered fled to shelter, but others remained determined to see out the whole seven-mile flotilla, even in torrential rain. Patrick Gunning had been waiting for the flotilla since 11 a.m. on Sunday. It was well worth the wait, he said. I've had my son Saul, who's 8, on my shoulders so we saw the whole thing, and we'll be staying a little longer. London's Metropolitan Police said as many as 6,000 extra officers were on patrol during jubilee events. Outside the capital, Britons gathered for thousands of jubilee-themed street parties and barbecues Sunday.