Maharaja Jai Singh II the founder of Jaipur had a great interest in astrology and built five observatories all over North India. He thus built Jantar Mantar in Jaipur which is the biggest stone observatory in the world. It is still a functioning observatory and recalls the ancient traditions and knowledge of Indian civilization. It is close to City Palace and you can club it with your visit to the palace. The observatory was not only built to study the universe and cosmos but also to garner an interest in astronomy. There are fourteen astronomical devices here for measuring time, tracking constellations and for observing the orbits around the sun. The world’s largest sundial- the ‘Samrat Yantra’ and other devices as the ‘Jaiprakash Yantra’ are still present here.