7. EXPLORE OLD-WORLD ASTRONOMY AT JANTAR MANTAR An equinoctial sundial and observatory that features 13 astronomical apparatuses built on a scale that is hard to imagine, Jantar Mantar is one of the best places to visit in Delhi with family and kids. Though the complex was built way back in 1724, some of the instruments are still well-preserved. The Samrat Yantra can pinpoint the location of planetary bodies and the direction of the North Pole while the Rama Yantra was meant to study the heights of stars from the surface of the earth.