Jantar Mantar New Delhi

This is one of five observatories built by Maharaja Jai Singh II, ruler of Jaipur. Constructed in 1725, Jantar Mantar (derived from the Sanskrit word for ‘instrument’, but which has also become the Hindi word for 'abracadabra') is a quiet park containing a collection of curving geometric buildings that are carefully calibrated to monitor the movement of the stars and planets.