Noboribetsu Onsen is one of Hokkaido's most famous hot spring resorts.
It has over 10 different kinds of water, containing minerals such as hydrogen sulphide, salt, and iron.
The quality of these minerals means the spa results in the world's most exceptional hot springs.
Noboribetsu is part of Shikotsu-Toya National Park.
The most impressive scene at the hot spring is the Jigoku Valley (hell valley), where yellowy gray volcanic gas seeps from the surface of the rocks.
This makes the whole place smell strongly of sulfur, and gives it an image like that of hell.
The valley is a 450-meter-diameter mouth of a volcano, which produces 3,000 liters of hot water a day.