there is a general feeling that the most powerful temples have a floor which is lower than the exterior. i was once told by a religious preacher that in such temples we descend with humbleness, and then ascend in life.
chidambaram you need to descend 21 steps to reach the temple floor.( of course finally you need to climb the raised ponnambalam. thirupathi is in a valley. other examples -thiruchendur, thirukadayur malapaadi and many other temples. the architects of these temples did an excellent job of rainwater exit linking the floor to the lower temple pond.