I recently visited 'Thiruvaiyaru - Tanjore' temple which is over 800 years old. This temple was build by Cholas and developed by many chola, pandiya kings.
Its in the banks of river Cauvery and worth place to visit if you are interested in architecture.
Years old paintings on the walls are must see one. Still vibrant with colours, but poorly maintained.
I have posted some photos of the temple here.
