That must be some highly compressive glass to be able to withstand such pressure.
In other words their hot spring could also double as a bomb shelter.
Just a little fact I read a long time ago, a piece of glass just 7mm can withstand 15~17atm despite being easy to break as a result of flying toward the ground.
Hot Springs!
Hot Springs!!It really is a hot springs!!!Completion
Abyssal Hot Springs