Step Well

When we think of being subterranean, we immediately think of being "under" ground, but this is not always the case.For some reason, photos of stepwells (bawdi, or baoli, or vav, in Indian dialects) have been tumbling out of 'blogs lately. Perhaps it has to do with the increasing interest in ecologically sustainable lifestyles. Stepwells are in most cases ancient Indian structures built in part to make use of a three-month monsoon season in the course of an entire year, but they have also come to serve cultural and religious purposes. To this end, the stepwells can be beautifully and ornately decorated. The structure of the steps themselves is a simple, pleasing pattern, but look to this post on DesignFlute for examples of how ornate and unique a stepwell can be.In essence, stepwells serve two very basic functions: to collect rain water, and to make it accessible. This account for the enormous basin shape, and the steps. From there, the designs can vary wildly, in part because these structures don't present any of the dangers of reservoirs or other continually renewing or flow-based water management structures. When the water only comes once a year, you might imagine a great deal of ritual can be built up around it, and the common necessity for these structures from place to place also inspires people to take creative responsibility, and identify with the particular details of their design and structure.
Stepwells present all sorts of fascinating combinations of pragmatic use and cultural significance, including a certain synergy of design and natural process. The silt that gathers in these structures comes to act as a natural water filter, for example, which is a quality that can be appreciated by animals as well as humans. One can imagine, too, the way in which a stepwell being the primary source for water during most of the year can develop into elaborate rituals and an appreciation for simple quantity. Just imagine the excitement and bounty of an enormous, full basin of clean water, and very gradually watching as it sinks lower, and lower, revealing more and more layers of steps to traverse, as the year progresses.Not all stepwells are wide-open to the sky, either. Many have structures built across their upper levels that allow rain through, but also provide shade and useful rooms and sub-levels for various uses in the drier season.
And then again, there's the steps.

Oh, those steps...
I have to imagine that every community has one or two epic legends about folks taking a tumble down the local stepwell just before the monsoon season, when it would take a particularly long (and jarring) time to reach the inevitable conclusion. I can't help but wonder, too, if some folks get especially adroit with maneuvering on those myriad pyramid-like step structures. Errol Flynn truly missed a great environment for showcasing his legwork, that's all I'm saying further on the matter.
Stepwells are water temples. They represent a magnificent, ancient solution to an absolute necessity.

Profound thanks to InfraNet Lab for a far more informative, yet somehow succinct, explanation of the function of these structures than any other source I was able to find.