Jantar Mantar
Astronomical observatories at Jaipur

"Between 1727 and 1734 Maharajah Jai Singh II of Jaipur constructed five astronomical observatories in west central India. The observatories, or "Jantar Mantars" as they are commonly known, incorporate multiple buildings of unique form, each with a specialized function for astronomical measurement. These structures with their striking combinations of geometric forms at large scale, have captivated the attention of architects, artists, and art historians world wide, yet remain largely unknown to the general public."

(from the site Jantar Mantar)
for full details and more pictures go to http://www.jantarmantar.org

 

Another interesting site is http://www.jaipur.org.uk/forts-monuments/jantar-mantar.html