The Jantar Mantar is located in the modern city of New Delhi, India.
It consists of 13 architectural astronomy instruments.
The site is one of five built by Maharaja Jai Singh II of Jaipur,
from 1723 onwards, as he was given by Mughal emporer Mohammed Shah
the task of revisiting the calendar and astronomical tables.
The research suggests 1724 as the actual year of construction.