The Jantar Mantar was built in 1710 in Delhi by Raja Jai Singh II of Jaipur (1699-1743). Situated near Connaught Place, this observatory consists of mason-built astronomical instruments to chart the positions of different planets, the sun, and the moon. Raja Jai Singh was an avid reader and astrologer; he wanted to learn about planets and therefore established four other such observatories, each at Ujjain, Jaipur, Varanasi, and Mathura (the Jantar Mantar in Mathura no longer exists today).
Location: Sansad Marg, Connaught Place, Delhi