The site – a 300-year-old collection of 20 scientific sculptures called yantra that can measure the positions of stars and planets, and precisely tell the time – had bemused me since my childhood here in Jaipur, when the structures seemed like giant versions of the delicate tools I kept in my school geometry kit. But years later, as a professional architect, I could better comprehend their use. They are ingenious architectural solutions to understanding the mechanics of astronomy, as well as key tools for traditional Hindu astrologers to craft birth charts and forecast auspicious dates.