The rapidly disappearing stepwells of India

These are just incredible.

“Construction of stepwells involved not just the sinking of a typical deep cylinder from which water could be hauled, but the careful placement of an adjacent, stone-lined “trench” that, once a long staircase and side ledges were embedded, allowed access to the ever-fluctuating water level which flowed through an opening in the well cylinder. In dry seasons, every step—which could number over a hundred—had to be negotiated to reach the bottom story. But during rainy seasons, a parallel function kicked in and the trench transformed into a large cistern, filling to capacity and submerging the steps sometimes to the surface. This ingenious system for water preservation continued for a millennium.”