The Jantar Mantar is a collection of architectural astronomical instruments; built in 1724 by Maharaja Sawai Jai Singh who was a Rajput king. The observatory consists of thirteen major geometric devices for measuring time; predicting eclipses; tracking stars' location as the earth orbits around the sun; ascertaining the declinations of planets; and determining the celestial altitudes and related ephemerides.

Delhi is said to be the site of Indraprashta; capital of the Pandavas of the Indian epic Mahabharata. Excavations have unearthed shards of painted pottery dating from around 1000 BCE; though the earliest known architectural relics date from the Mauryan Period; about 2;300 years ago. Since that time the site has been continuously settled.

The city was ruled by the Hindu Rajputs between about 900 and 1206 CE; when it became the capital of the Delhi Sultanate. In the mid-seventeenth century the Mughal Emperor Shah Jahan (1628-1658) established Old Delhi in its present location; including most notably the Red Fort or Lal Qila. The Old City served as the capital of the Mughal Empire from 1638 onwards.

Delhi passed under British control in 1857 and became the capital of British India in 1911. In large scale rebuilding; parts of the Old City were demolished to provide room for a grand new city designed by Edward Lutyens. New Delhi became the capital of independent India in 1947. Pictures From Asia David Henley