Gadisar Lake was dug in the 14th century by Maharawal Gadsi Singh as a rainwater reservoir to supply the city. It is still fed by monsoon runoff and surrounded by small temples, chhatris (domed cenotaphs), and ghats descending to the water's edge. The lake attracts migratory birds in winter, and in the early morning you will find local residents performing puja on the ghats, fishermen setting out, and priests making offerings in the temple courtyards.
The walk around the lake takes about 30 minutes. Boats can be hired at the main ghat for a short ride on the water — a good way to see the ghats from the lake side and get a view of the fort rising above the town. The surrounding chhatris and shrines are in various states of repair; several are beautifully maintained while others are quietly crumbling. The stone gateway at the main entrance, the Tilon ki Pol, is particularly fine and worth stopping at before entering.
The lake is at its best in winter (November to February) when the light is soft and the water level is high after the monsoon. Go early morning if you can — by mid-morning the boats fill up with tour groups.