The Jantar Mantar is an observatory built in 1710. The building structures are used to record the positions of celestial objects like the sun and moon. It was built by a maharaja for his own use as he was an avid astronomer.
We spent the day yesterday visiting sites around Delhi. In addition to the Jantar Mantar, we also visited the National Museum, Rajghat Gandhi Samadhi (memorial for Gandhi), and the Akshardham temple. The Akshardham temple was opened in 2005 (after 5 years of construction) and is still being worked on. It was built with a mix of styles around India and build as ancient temples were, with sandstone and marble featuring no concrete or steel. The architecture and hand carved detail is absolutely stunning and the Guinness book of world records recognizes it as the world's largest Hindu temple. Sadly, they do not allow cameras, but I don't think pictures would do it justice anyway.
Today is a work day and then tomorrow its off to Jaipur.
Technical Specs: Canon 40D, 17-55 @ 17mm, f/5.6, 1/640s, ISO 100.