India, Oct. 19 -- For those of you who have seen the new Rs 100 note, you would have noticed that there is a stepwell featured on it. Stepwells are a common feature across many parts of western India and were commonly used by Rajput kings and their predecessors in the earliest example of rainwater harvesting. Many of them have fallen into disrepair and disuse though they were all ornate at one time. Many, because they were often associated with religion, were destroyed when invading armies came into the region. But not the stepwell we see on the Rs 100 note. The Rani Ki Vav at Patan, Gujarat, survived thanks to it being covered in sand and mud.

Whether that was a deliberate act to protect it from armies that raided the prosperous traders...