Alappuzha is famous for its backwaters and houseboats. It's one of the quietest places on earth. 

 To quote National Geographic : "Blessed with postcard-perfect beaches, verdant paddy fields, shady coconut groves and friendly folk, Kerala is the ideal place to slow the travel pace. You can paddle in the warm waters of the Arabian Sea, indulge in an Ayurvedic treatment, and savor scrumptious seafood while slowly gliding through the breathtakingly beautiful backwaters."