Final answer:
The Jantar Mantars are a collection of astronomical instruments built by the Rajput king Sawai Jai Singh II, and they are located at various places in India, including Jaipur, Delhi, Agra, and Varanasi.
Step-by-step explanation:
The Jantar Mantars are a collection of astronomical instruments built by the Rajput king Sawai Jai Singh II. They are located at various places in India, including Jaipur, Delhi, Agra, and Varanasi. The Jantar Mantar in Jaipur is the largest and best-preserved one, consisting of several large instruments used to observe and study celestial bodies. The Jantar Mantar in Delhi is also significant and attracts many visitors.