The largest natural crater in the world has a past almost as awe-inspiring as its present.
What is now Makhtesh Ramon in Israel's harsh but beautiful Negev desert began life as one of five asymmetrical mountains jutting out of a shallow sea that couldn't make its mind up about where it wanted to be.
Three times the sea came and went, each time eroding more of Ramon's soft core, but leaving the harder shell intact. Tectonics also played their part, causing further central collapse. Effectively Ramon and the other four mountains imploded, forming what are collectively known as the makhteshim. For reasons unknown, the phenomenon has occurred nowhere else on Earth. The makhteshim are, or so the guides claim, unique.