The geothermal water here is classified as 'green sulfur spring,' one of only two places in the world where it is found.
Historical records indicate the site was once referred to as 'Hell Valley' because of the rising steam and dangerous temperatures.
The high acidity of the water can reach a pH as low as 1.4, which is highly corrosive to most metals.
The water contains trace amounts of radioactive elements like radium, which were studied for potential therapeutic uses in the early 20th century.
The valley is the source of the Beitou Creek, which is one of the few places in the world where a radioactive mineral named 'hokutolite' is naturally deposited.
Thermal Valley is a geothermal volcanic crater located at the head of the Beitou hot spring area in Taipei. The site features a natural spring with water temperatures ranging from 80°C to 100°C. Due to the high sulfur content and mineral composition, the rock formations exhibit a distinct jade-green color, earning it the historical nickname 'Hell Valley' or 'Ghost Lake.' Steam consistently rises from the water surface throughout the year, creating a unique microclimate and visual effect. The area includes a surrounding perimeter trail that allows visitors to view the geothermal activity safely. It is one of the few sources of 'green sulfur springs' in the world, a rare geological phenomenon. The spring water is acidic, with a pH level between 1.4 and 1.6. It serves as a primary source for the many hot spring hotels located in the immediate vicinity.
The main viewing platform at the end of the entrance path, which provides a panoramic view of the steaming lake.
Bring a bottle of water, as the high humidity and sulfurous heat can be dehydrating.
Stay on the designated wooden walking paths, as the ground outside these areas can be unstable and dangerously hot.
Visit on a cooler or overcast day to better appreciate the visual contrast of the rising steam.
Avoid touching any metal railings or surfaces for too long, as they can become very hot from the ambient steam.
Closed on Mondays for maintenance.
Do not touch the water or attempt to cook food in the springs; stay behind safety railings.
