I've written a number of times of a full timer benefit, time to learn and read.
I'm now reading a book on the formation of the planet Earth. The section I'm on is describing the formation of the Hawaii islands by the Hawaiian Hotspot, The hotspot is a large deep magma chamber. It's eruptions have created the Hawaiian Islands. Actually it's created a chain of islands that extend to Siberia.
The remnants of these islands are called the Emperor Seamounts and can be clearly seen in the attached picture, stretching 3600 miles across the Pacific. It is believed that the hotspot is relatively stationary and that the bottom of the Pacific ocean moves creating the chain.
In the attached picture Hawaii is in the middle, North America to the right and Asia to the left. Be sure to double click the picture.
Another prominent hotspot is the Yellowstone hotspot. The following link has info on that. I recall that Craters of the Moon is one of them.
Strictly this may not be a forum topic but it is an inkling into the freedom of full time retirement and Yellowstone, a place everyone should go.
Yellowstone hotspot - Wikipedia, the free encyclopedia
The above link to the Yellowstone Hotspot shows the chain of Yellowstone Caldera. We've only been to two but now the others are on my list. So much to do...