Connaught Place, Delhi
An 18th-century astronomical observatory built in 1724 by Maharaja Jai Singh II of Jaipur, one of five such Jantar Mantars he constructed across northern India. Its collection of large masonry instruments, including the towering Samrat Yantra sundial, were designed to track celestial positions, predict eclipses and measure time with remarkable precision for their era. The observatory reflects the fusion of Indian and Islamic astronomical traditions under Jai Singh's patronage. It remains a rare surviving example of pre-telescopic astronomical architecture.