Jantar Mantar is an 18th-century astronomical observatory in Jaipur, built between 1728 and 1734 by Maharaja Sawai Jai Singh II, the city’s founder.
The site holds 19 monumental stone and marble instruments, including the world’s largest stone sundial, all designed to track the positions of the sun, moon, and stars with an accuracy that rivaled contemporary brass instruments elsewhere in the world. A UNESCO World Heritage Site, it is the largest and best preserved of the five observatories Jai Singh commissioned across northern India.
Most visitors spend about an hour walking among the instruments, though astronomy enthusiasts often stay closer to two hours, especially with an audio guide explaining how each device once measured time and celestial movement.
