Jantar Mantar is the most famous and elaborate observatory of its time.

It was constructed in the year 1724 A.D. by Sawai Jai Singh II, even before the city of Jaipur was built, and has been described as the most surrealistic and logical landscape instone.

It was built to measure the local time, the sun's declination, altitude, the declination of stars, planets and to determine eclipses.

The Western skyline is dominated by the extensive walls, watch towers and gateways of Jaigarh built by Jai Singh in 1726. It is one of the few military structures of medevial India preserved almost intact, containing palaces, gardens, open and covered reservoirs, a granary, an armoury, a canon foundary and several Temples. It was the royal treasury for several years. The world's largest cannon on wheels is to be found here. The fort has its own museum and provides an excellent view of Amer Palace.