Natural Arch, Tirumala hills is a distinctive geological wonder located 1 km (0.6 M) North of the Tirumala hills temple, near the Chakra Teertham in the state of Andhra Pradesh, India. The Arch is also called Silathoranam in local language (Telugu language: “Sila” means ‘rock’ and “thoranam” means a garland strung over a threshold, connecting two vertical columns or an ‘arch’ as in this case). The arch measures 8 m (26.2 ft) in width and 3 m (9.8 ft) in height, and is naturally formed in the quartzites of Cuddapah Supergroup of Middle to Upper Proterozoic (1600 to 570 Ma) due to natural erosive forces. Since the rock look likes and appears to be the hood of a serpent, a conch and a discus, it is conceived that this source is dedicated to Lord Venkateshwara idol.

Geologists have identified the rocks on the hill as pre-Cambrian that dates back to millions of years ago. It is said that there are only two other sites like this in the entire world itself. The other two are the one that cuts through the headland of the Dalradian Quartzite in Ukand and the Rainbow Arch Bridge of Utah in USA . Geologists found out Silathoranam accidentally whilst excavating a geological fault on Tirumala Hills. This wonderful phenomena of nature has been subjected to various schools of thoughts. Some are of the view that it could be the effect of a wave action from oceanic transgression or intensified climatic settings and corrosion.