The Palio di Siena (known locally simply as Il Palio) is a horse race that is held twice each year, on July 2 and August 16, in Siena, Italy. Ten horses and riders, bareback and dressed in the appropriate colours, represent ten of the seventeen contrade, or city wards.
The Palio takes place in the town square.
The embedded video was taken by the RAI, Italy's national television network, in 1962.
There are much better, newer videos on YouTube but I like this one because it does not have the smoothness of a modern sporting event and goes into what the Palio means for the city. I see Fellini's films of that period in it.