Commonly thought open cave
All of these caves have been explored and verified by experts.
These caves have been confirmed to be safe to open to the public.
In fact, most of the unexplored cave exploration is like this way.
You have to crawl through space that barely fits your body.
The road is kind and invisible, so proper equipment.
It’s very dangerous if you’re not properly trained.
Especially if the person ahead of you has a seizure or falls down,
Everyone in the back is in danger, even if the rescue team is coming.
Difficulty in structure due to difficulty in knowing where it is
If you go into an unopened cave by yourself without an expert,
be very likely to die