Ram Yantra in Jantar Mantar Jaipur

Ram Yantra in Jantar Mantar at Jaipur is made of circular walls and the floor graduated observing altitude and azimuth (arc of the celestial great circle from zenith to horizon) of the heavenly bodies.

Jantar Mantar at Jaipur, built by Maharaja Sawai Jai Singh II, is one of the largest stone observatories in the world.