Jaipur, India: Narivalaya Yantra (N. Sundial) at Jantar Mantar (Observatory).(Jaipur is the capital of Rajasthan State.) The Narivalaya Yantra measures time between the vernal and autumnal equinoxes. (Another sundial, the Southern Sundial, measures time between the autumnal and vernal equinoxes.) Built in the early 18th century, the Jantar Mantar (Observatory) is a UNESCO World Heritage Site.