Rowing boats begin to gather on the River Thames, London, during the Diamond Jubilee river pageant, Sunday, June 3, 2012

Rowing boats begin to gather on the River Thames, London, during the Diamond Jubilee river pageant, Sunday, June 3, 2012. (Anthony Devlin/Press Association via AP Images)

(CBS News) It's a historic sight that's fit for a queen. Some are calling it the biggest gathering along the banks of the River Thames in 350 years, as both royals and dignitaries prepare for this morning's Diamond Jubilee Pageant. Queen Elizabeth II is the the pageant's honoree . . . so from the great rivers and backwaters of the realm, boats are on the move to join The Queen in the Diamond Jubilee Royal River Pageant.

Canaletto's "The Thames on Lord Mayor's Day," dating from before 1752 - a grand tableau of a royal river pageant organized for the then-King George II. 

(Credit: CBS News)