On a September afternoon in 1870, a party of nine explorers, eight army escorts, and two cooks made its way by horseback along the Firehole River in an untamed corner of Wyoming. Their task was to explore the mountains and valleys of an ancient volcano crater, an area known for geothermal activity. Nathaniel P. Langford, a member of the expedition, later recalled what met their gaze that September day:

Judge, then, what must have been our astonishment, as we entered the basin at mid-afternoon of our second day's travel, to see in the clear sunlight, at no great distance, an immense volume of clear, sparkling water projected into the air to the height of 125 feet. "Geysers! Geysers!" exclaimed one of our company, and, spurring our jaded horses, we soon gathered around this wonderful [sight]. It was indeed a perfect geyser … It spouted at regular intervals nine times during our stay, the columns of boiling water being thrown from 90 to 125 feet at discharge, which lasted from 15 to 20 minutes. We gave it the name of "Old Faithful."

Old Faithful in Yellowstone National Park earned its name for the predictability of its eruptions. It's still predictable today. In Langford's day, the only way to witness Old Faithful was to travel to Wyoming, a trip requiring expense, difficulty, time, and danger. But today anyone with Internet access can watch the geyser erupt in real time.