Well, I found a cool cave today. Coordinates and seed are in the screenshot, if you want to go there yourself. Or you could come see it at minetest.0gb.us:30001, but I'm going to mine part of it, so it won't look as nice..
I was clearing some gravel underground, When I found this lavafall. It looks like a lake of the stuff is missing a chunk of its border, so it's just spilling out.
What a drop .... and there's more lava down there.
Best not mess with this. The lava would update, and flow everywhere.
Iron, coal, gravel, AND mese? So tempting. But I wouldn't want to get the lava flowing.
It's hard to tell what it is in the shot, but that's mese in the ceiling. And a lot of it. But it's way to high to reach, and is above lava anyway.