Down from the Sansad Marg from Connaught Place, salmon-coloured structures called as 'Jantar Mantar' is located. It is one of Maharaja Jai Singh's observatories. The Mughal Emperor Muhammad Shah entrusted the famous astronomer Maharaja Jai Singh Second of Jaipur with the task of revising the calendar and correcting the astronomical tables.
Janatr Mantar was built in 1725 and it is slightly small in size than the observatory located at Jaipur. A huge sundial called as the Prince of Dials dominates it. Many other instruments plot the heavenly bodies as well as predict eclipses.