Kayaking Silver River, Florida - cypress swamp springs and manatees

Across North-Central Florida (not the panhandle) is a unique combination of karst geology, low elevation, and consistent year-round heavy rainstorms. This creates a vast network of completely flooded caves, which in turn create very strange and spectacular high-flow springs and rivers. Most everywhere else in the world, crystal clear spring water is quickly diluted - but the sheer volume of water in North Florida, along with a healthy balanced ecosystem of water plants, allows the waters to remain crystalline across vast areas of swamps and rivers.
The clearness of the water allows for many kinds of river bottom-anchored aquatic plants to thrive, which outcompete invasive lily pads and other surface plants. Freshwater seaweed and seagrass are the most efficient carbon-fixating kinds of plants, so they pump tons of food and nutrition into a small area, allowing for huge amounts of animal life.
Thus we get to see an incredible abundance of life, at unusually high population densities, through crystal-clear water untainted by silt and tannins. A perfect window into a perfect underwater paradise.