This one also got into the ‘Too cool’ category, and it’s a favorite of mine. This is (I’m pretty sure – again, Jim didn’t tell me when he sent the stack of photos) a geothermal vent that passes through a layer of grey clay, and so produces a witches cauldron of bubbling mud. And Jim was able to capture one of the bubbles as it popped. It’s a shame it doesn’t stand out better against the immediate background, but I doubt there were a lot of positioning or lighting options at hand.
I wonder if he got video?