The Ramalinga Vilasam Palace, also known as the Ram Vilas Palace, is the former residence of the Sethupati rulers of Ramanathapuram. The palace contains a collection of murals depicting episodes from the rulers' history — their battles with the Marathas, their dealings with the British East India Company, and their relationship with the Rameshwaram temple. The portraits of successive Sethupati rulers in their durbar dress are striking.
The palace is not a polished museum and access can be inconsistent, but it's worth making the effort. The paintings inside, though faded, are among the best examples of late Maratha-period court painting in Tamil Nadu, and the building itself — a sprawling complex of courtyards and pavilions — gives a sense of provincial grandeur now somewhat faded. Ask at the gate if it can be visited.