We hiked around two lakes at Yosemite (well, one we hiked all around, the other was a bit too large for that). Mirror Lake is a beautiful placid lake in the floor of Yosemite Valley. We hiked around the perimeter.
Hetch Hetchy Lake is a lake in another area of Yosemite, and it is the water source for all the San Francisco Valley. It was recommended to us by other hikers. It had several waterfalls that fed into the lake. The biggest was Wapama Falls where there was a series of bridges where you could walk near the falls and get wet!
