Jantar Mantar is an observatory, which was built in the year 1737 by Maharaja Jai Singh of Jaipur. Jai Singh was a great admirer of science and technology and was particularly passionate about astronomy. He sent scholars abroad to study foreign observatories before construction (of observatories) began. Astronomers return with several manuals on astronomy. The Jantar Mantar in Varanasi was built in line with the Delhi, Mathura, Ujjain and Jaipur observatories.
Jantar Mantar was created to measure local time, to announce the Sun, the elevation, the declaration of stars, to determine the planets and eclipses, to record the speed, speed and properties at Jantar Mantar in Varanasi and planets and astronomy There are many masonry instruments to study. It is accurate and can still be used efficiently today. Jantar Mantar encompasses many structures of unique form, each of which performs a special function for astronomical measurements.