The Soda Springs
Yellowstone may have its geysers and France its champagne, but Yosemite has the Soda Springs, puddles of carbonated water percolating up from nowhere (if you consider the earth to be nowhere, at least, in which case you're welcome to go right back to whatever trendy planet you came from). The bulk of the springs have been corralled inside the log enclosure, though a few remain outside, wild and free - the puddle at the photo's lower left, for one. Elbow your way to a position near one of the springs, and you can watch bubbles appear before your unbelieving eyes! It's probably best to skip Soda Springs to keep the rest of your life from being anticlimactic.