5 hours ago, kayb said:
There are volcanic hot springs in Hakone, Japan, where employees cook eggs in the mineral-heavy water and sell them at stands. The shells are black and pitted due, I guess, to a reaction between minerals in the shell and in the water. The eggs have a salty taste.
They have those in Iceland also. There's a small town that revolves around hot springs and tourists can both cook eggs in the water and they also bake bread in the hot steam. Sulfury bread. Yum.
But the hot springs are great for soaking after a long hike. Our first hotel had a spring on their property and they fed it into a series of natural pools for bathing/soaking.