Yes! You read the title right! The world's largest stone sundial is Jantar Mantar which is situated in Jaipur, India. It is undoubtedly the amazing monument which is constructed in such a manner which shows the time of the day using the shadows of the sun, particularly observation of astronomical positions with the naked eye.
Jantar Mantar deploys all three ancient coordinate systems of the five celestial coordinate systems known. It is very astonishing to see that how logically this monument was constructed depicting time.
It still stands as historic monument of importance. It is worthy to visit.