Jantar mantar is one of Jai Singh's five remarkable observatories. Constructed with stone and marble its complex instruments whose settings and shapes are precisely and scientifically designed represent the high points of Medieval Indian astronomy. The Ram Yantras used for gauging altitudes are unique in their isolation. this is the largest of the five observatories founded by Sawai Jai Singh-II in various parts of the country.

Major Yantras or instruments that you can watch moving clockwise are: Small 'Samrat', 'Dhruva', 'Narivalya', The Observer's Seat, Small 'Kranti', 'Raj', 'Unnathamsa', 'Disha', 'Dakshina', Large 'Samrat', 'Rashivalayas', 'Jai Prakash', Small 'Ram', Large 'Ram Yantra', 'Diganta', Large 'Kranti'.