This is in a village Thondanur , Karnataka.
Sri Ramanujar, Jagadacharyar stayed in Thondanur after He left Srirangam. With His guidance this lake was created and He named it Thirumalasagara. According to records Tipusultan visited this lake and found pebbles in the clear water of this lake and named it Moti talab.
This lake never dried up since its creation even during drought conditions.
There is a temple near this lake. This temple houses Yoga Narasimhar and Ramanujar.
Ramanujar always prayed to Narasimhar whenever He started any kainkaryam. During His stay in Karnataka the king Vishnuvardana who was a disciple of Ramanujar supported him in all his services.
This lake is an example of how Ramanujar was a holistic leader. His focus was not just bhakthi but weaving it into people's life through things that affect them on daily basis.
He saw water running away and getting wasted between the two hills and created this lake to put water to good use. This water serves the nearby villages and helps them grow crops.
