Tucked away in the Norris Geyser Basin is Steamboat Geyser, the world's tallest active geyser. Its major eruptions shoot water more than 300 feet (91 m). Only Waimangu Geyser in New Zealand has rocketed to greater heights—but not in more than one hundred years. In Yellowstone National Park's recorded history, only two other geysers have exceeded Steamboat in size: Excelsior Geyser in Midway Geyser Basin and Sapphire Pool in Biscuit Basin. Steamboat's minor and major eruptions are entirely unpredictable.