Beppu boasts the largest volume of hot spring water in Japan, and hot steam, mud and water have been naturally erupting throughout the city for well over 1,000 years. Since some point in time, the hot springs that gush out from underground have been called jigoku, or Hells, and the jigoku meguri—a tour where you can enjoy the different colors and formations of each Hell—has become Beppu’s most popular tourist attraction. There are seven Hells in Beppu, and you can visit them all in about a half a day using a common pass.
The beautiful cobalt blue of Umi Jigoku comes from the iron sulfate dissolved in the water. Its temperature is a near-boiling 98 degrees centigrade. The eye-catching Chinoike Jigoku, which evokes visuals of Hell itself, is a pond of red hot mud containing iron oxide, magnesium oxide and other substances that has bubbled up from beneath the earth. Tatsumaki Jigoku, a geyser that spews 105-degree hot water about 30 m into the air, has been designated as a natural monument of Beppu City. On the jigoku meguri, visitors can also enjoy strolling around Beppu and seeing columns of hot spring steam rising up into the air.