India has some of the oldest temples in the world. Some of it are built over and over old temples, so no one is sure of its age. There are myths associated with several temples, which are associating stories of several millenniums back.
Some of them are standing exhibits to mastery of astronomy, complex architecture and engineering of that era. Ellora Temple, Brihadeeshwara temple are so brilliant that even with todays modern technology, one cannot replicate it.