Ahom king Swargadeo Rudra Singha dug the Joysagar tank, the world's largest man-made tank covering an area of 318 acres (1.29 km2) including its four banks in memory of his mother Sati Joymati. On its bank in 1703 he built the Rangnath Dol, a (Shiva) temple near the Borduar or main gateway on way from the Joysagar tank to the Talatal Ghar to offer prayer to Lord Shiva. Large numbers of devotees continue to visit and offer puja in this temple.
References
Rangnath Dol Wikipedia(Text) CC BY-SA