Turanzu's Forge

Turanzu's forge is the worlds largest volcanic caldera based in Lumi. A literal lake of hell which looks like a firey ocean bubbling in super hot lava.
The forge has been calculated to be around 250 million years old, however it is currently unknown to the citizens of Gleron to how it formed as to how large it is and the fact its still boiling over to this day. A few theorists believe it was formed from a large meteor which was traveling at such velocity that it punctured deep into the top half of the lower mantle, others believe it was formed from a precursor civilization who detonated an ultra powerful weapon and while others believe it formed from natural geographic causes.
The caldera is constantly erupting but luckily due to the position the lava heats up and cools constantly around the edges so it does not go anywhere.
Many scientists are attracted to the location as it is one of the few geographic wonders of the world.