The Delhi Observatory (Jantar Mantar)
Brihat Samrât Yantra (Giant Equatorial Sun-Dial)
It is on the north-south axis, and its hypotenuse turns to the polar star.
Both wings have graduations to show the exact time by the shadow of the hypotenuse.
The height of the right triangle is 21 meters, and the base 35 meters.
This observatory park is open to the public with an admission fee.