After visiting Old Faithful, we drove further north on the road, and stopped at the Fairy Falls parking area. We then hiked 0.6 miles until we reached a fairly obvious unmaintained trail on the side of the mountain. We quickly scrambled up the mountain to get an unparalleled view of Grand Prismatic Spring, the largest hot spring in Yellowstone. Very few people know about this opportunity, and instead try and view the spring from the boardwalk. The problem is that the spring is so large, it is impossible to take a worthy picture that includes the entire hot spring and it's vibrant colors. It was definitely one of my favorite photographic subjects in Yellowstone. The runoff streams produce a rainbow of colors that are dependent on the temperature of the runoff water. Yellow bacteria are found in the hotter waters close to the spring; orange, red, and brown grow in progressively cooler waters. We then headed further north and took the 0.5 mile boardwalk around Midway Geyser Basin, again viewing the famous Grand Prismatic Spring and Excelsior Geyser Crater from a different perspective. I definitely recommend climbing up the hill to get the unparalleled view, though!