Waving "ta-ra now!" outside Greek temple (6,3)

'temple' is the definition.
(angkor wat matches up with the definition temple)

'waving ta-ra now outside greek' is the wordplay.
'waving' indicates an anagram (letters wave around).
'outside' indicates putting letters inside (some letters go outside others).
'greek' becomes 'gk'.
'ta'+'ra'+'now'='taranow'
'taranow' with letters rearranged gives 'anorwat'.
'anorwat' placed around 'gk' is 'ANGKOR WAT'.