The park’s hydrothermal systems are among the most mysterious places on Earth. The iconic geyser erupts every 90 minutes, on average, like clockwork and lasts for up to five minutes. The eruptions reach as high as 130 feet, clearing 180 feet. One way to see the geyser’s power is to join the crowds of tourists. Another is to go to the less crowded place in the dining room of the nearby Old Faithful Inn. The thrill-seekers may want to consider the mile-long hike out to Observation Point for a bird's-eye view of the Upper Geyser Basin.