This is a special destination in Jaipur built during 1727 and 1733 by Maharaja Jai Singh. It is the largest stone observatory in the world with amazing features. JantarMantar is also known as Yantra Mantra, which means instruments to measure time. It is a collection of astronomical instruments and consists of instruments which were scientifically designed. These were used to gather some knowledge of the celestial bodies and were used by the people who were interested in astronomy. Even today this observatory gives accurate details. Constructed with stone and marble, it has fourteen statistical instruments for measuring time and predicting eclipses.