India, Oct. 18 -- Jantar Mantar in New Delhi is much in the news today, but how many of us are aware of its history? A monument conceived to measure the movements of celestial bodies has become a place where citizens seek to measure the distance between the promises of the state and the realities of their lives. Built to interrogate the heavens, it has become a forum for interrogating those who govern us. Its history is a reminder that monuments do not remain imprisoned in the purposes for which they were constructed. They acquire new meanings as the societies around them change.

Jantar Mantar was built in 1724 by Maharaja Sawai Jai Singh II of Jaipur, a ruler whose interests extended well beyond the conventional preoccupations of kingsh...