The temples of the Sangam age were built out of perishable materials such as plaster, timber and brick, which is why little trace of them is found today. The only public structures of any historical importance belonging to this age that have survived to this day are the rock-beds hewn out of natural rock formation, that were made for the ascetics. The "Silappatikaram" and the Sangam poems such as "Kaliththokai", "Mullaippāṭṭu" and "Purananuru" mention several kinds of temples such as the "Puranilaikkottam" or the temple at the outskirts of a city, the "Netunilaikkottam" or the tall temple, the "Palkunrakkottam" the temple on top of a hill, the "Ilavantikaippalli" or the temple with a garden and bathing ghat, the "Elunilaimatam" or a seven storeyed temple, the "Katavutkatinakar" or the temple city.