Living as they are in a land-locked country, the Czechs have developed a passion for their rivers. And so every Summer the rivers become highways for masses of rafts and canoes of all description as they all 'take to water', as they call it, for a week or two. Some do it year after year, well into their middle-age, but I don't know any Czech who wouldn't have done it at least once in their lifetime, when young, as it is considered to be one of the most important rites-of-passage.
It used to be a more adventurous undertaking 'in the old days' - you'd start at the point where the river becomes navigable and then let the flow take you over calm waters as well as over the rapids, stopping here and there for a bite to eat (inevitably prepared around a campfire and using as many free ingredients such as fish you might have caught or food found in the vicinity, such as mushrooms). Sleeping was done 'under the stars' or in small primitive tents, and the whole ethos was one of being at one with Nature.
Nowadays the rite-of-passage involves more alcohol, and the sleeping happens mostly in privately owned campsites that have sprung up along the banks - this is one result of the country becoming business-minded in its post-Communist era.
But not all is lost; while the concentration of canoes can be scary in places like Krumlov and the camps, if you actually take a canoe you can find yourself drifting through breathtaking gorges and forests and not feel crowded at all. And it is still possible to find a solitary spot under a tree and sleep under the stars.