Ta Keo, constructed around 1000 AD under Jayavarman V's reign, is now over 1020 years old. This temple-mountain, possibly the first entirely built of sandstone in Angkor, Cambodia, was dedicated to Shiva. Unique for its massive, undecorated appearance due to halted construction, Ta Keo was intended as Jayavarman V's state temple. Its significant, unfinished state and the absence of external decorations distinguish it from other Angkorian temples, reflecting its potential as a monumental structure had it been completed.