Midway Geyser Basin
This was probably by far my favorite. The colors were amazingly brilliant. And the size of the crowds did not disappoint, either. The star attraction by far is Grand Prismatic Geyser, with its myriad colors - it is utterly kaleidoscopic. There is Turquoise Pool (the first one you will encounter), Excelsior Geyser and Opal Pool, which both are brilliantly blue.