Yellowstone Park is famous for its geysers and other geothermal wonders as well as its wildlife. During the summer it is not uncommon to get caught in traffic jams with bison who are moving in large herds during the early morning hours. My reaction to this Buffalo Jam was to photograph the people reacting to this incredible event rather than the bison. The event lasted a good 90 minutes during which time the park traffic lined up for miles.