Bizarre and unearthly, these deceptively picturesque structures are found mostly in west central Florida, the unfortunate result of mining phosphorus to make fertilizer.

Phosphorus, one of the key ingredients behind the green revolution of the 20th century, has helped maximize farm yields worldwide. But obtaining raw material for fertilizer is hardly a green process. Miners pull phosphate ore out of the ground, crush it, and throw it into an acid lake, where it separates into white gypsum stacks and a liquid acid that is then processed further to feed crops.