https://timbu.com/japan

The image above shows the Umi-jigoku 「海地獄」, which is known as “Ocean” or “Sea” Hell. It is a hot spring, but too bad you can't go swimming in it… because it is bubbling away at 98°C.

There is another smaller red/orange hot spring within the Umi-jigoku site called Akaike Hell. The site isn’t too big, but there are lots to see and do, so while you could rush through in 20 minutes, it’s best to take at least an hour to see everything it has to offer.

There are many aesthetic points from which to see the main Umi-jigoku hot spring, from on the mountain, up close at ground level and the “observation deck”.
Things you can do at Umi-jigoku:

    #Visit the “White Dragon” shrine.
    #Visit the souvenir shop.
    #There is a mini-museum with history about the hot spring.
    #Eat at the restaurant featuring “Hell Steamed Pudding” and chanpon, a noodle dish with an egg steamed in     the waters of Umi-jigoku. Cool right!!!!!
    #At a more appropriate temperature you can enjoy a foot bath 「ayushi, 足湯」.

The Umi-jigoku is a National Site of Scenic Beauty. Next time you think to visit Japan or if you are in Japan this is a must see site.