The seven hells are as follows.
1 Sea Hell

This is the largest hell place, best managed as a sightseeing spot. The best feature is a steaming hell pond of cobalt blue. This amazing color results from the dissolution of iron sulfate, one component of hot springs.
There are two ponds with water tropical lilies floating and one green house for gigantic water lilies.
Lily ponds are one of the images of Heaven, but nobody feel
2 Oniishi Bozu Hell

Onishi means “ogre rocks (ogres are the residents of Hell).” Bozu means “Buddhist monk,” and “shaven head (the monk’s head is totally shaven). In this hell, there are several muddy ponds. The steams coming from the underground make little mud domes. They just look like the shaven monk’s head.
It was once closed, but it was newly arranged and got open to the public.
3 Furnace Hell

Kamado Jigoku is the Japanese name. Furnace is Kamado in Japanese. Kamado is mainly used for boiling rice. So as a typical image, a big rice pot is put on Kamado. The name comes from the nearby shrine Kamado Shrine (Kamado shrine itself has nothing to do with furnace, and it happens to read the same way).
This hell has a lot of distinctive ponds, but the very good point about this is its entertainments, such as shops, little experimental shows of smoking, hot water drink, foot baths, and phot spots. This is a kind of small Jigoku amusement park.
4 Oniyama Hell

Rather than the name of Oniyama, Ogre Mountain, it should be called Crocodile Hell. In Buddhism, no crocodiles or alligators appear, but don’t point it out. They may be suitable for hell worlds.
Now there are 80 crocodiles or alligators. (FYI: Crocodile’s snout is triangle-shaped, while alligator’s one is flat.)
5 Shiraike Hell

Shiraike means “White Pond,” but, actually, the pond is greenish white.
It has a small tropical fish aquarium, where you see pirarucu, arowana and piranhas.
6 Blood Pond Hell

Chinoike Jigoku is the Japanese name. Blood pond is one of the torture places in Hell, along with a boiling water or needle mound. This name is truly suitable for the name of Hell place.
It is the oldest natural hell in Japan. This red color results from the dissolution of iron. This place sells special skin ointment made from the clay here. And it has a large souvenir shop.
7 Tornado Hell

This is a guizer. It spouts out every 30-40 minutes. The water hit the roof very hard.
Without the rock roof top, it would spurt up as high as 30 meters, and the visitors would get splashes of boiling water.