Jantar Mantar’ was built in 1724 by Raja Jai Singh II of Jaipur in Delhi. Jantar Mantar of Delhi, is an astronomical observatory with masonry instruments. Jantar Mantar in Delhi is a remarkable and curious creation of Raja Jai Singh II, the mathematician and astronomer king.Jantar Mantar has instruments that can graph the path of the astronomical universe. Jantar Mantar means ‘instrument for calculation.’ There is a colossal Samrat Yantra at the periphery of Jantar Mantar. To the south of Samrat Yantra there is an amazing instrument called Jai Prakash.Jantar Mantar is built of brick rubble that is plastered in lime. The following instruments are inside the Jantar Mantar of Delhi- Samrat Yantra, Jai Prakash, Ram Yantra, Niyati Chakra, Misra Yantra. All these instruments can be used for various astronomical calculations.