Step 1: Locate each site: Hampi is in Karnataka, Sanchi Stupa is in Madhya Pradesh and the Konark Sun Temple is in Odisha. Step 2: Jantar Mantar in Jaipur, an astronomical observatory built by Sawai Jai Singh II in the 18th century, was inscribed on the World Heritage list in 2010. Step 3: Other World Heritage Sites in Rajasthan: Keoladeo National Park (1985), the Hill Forts of Rajasthan (2013) and the Walled City of Jaipur (2019). Answer: Jantar Mantar, Jaipur.