Viharas were for the purpose of living, Chaityas were assemblies for the purpose of discussions. Further, Chaityas were with Stupas, Viharas did not have stupas.
The third Sangam was held at the present Madurai in Tamil Nadu. The third sangam had 449 poets and the important ones among them include Nakkirar, Iraiyanar, Kapilar, Paranar, Sattanar, Auvikyar etc.
The famous Chola king Karikala of the Sangam age is credited with constructing a dam on the Kaveri river. It is considered to be the earliest dam in the country.