Millions enthralled by me and my historic site (7)
I believe the answer is:
memphis
'historic site' is the definition.
(ancient Egyptian city)
'millions enthralled by me and my' is the wordplay.
'millions' becomes 'm' (abbreviation).
'enthralled by' is an insertion indicator ('enthral' can mean 'capture').
'and' is a charade indicator (letters next to each other).
'my' becomes 'phis' (I can't justify this - if you can you should give a lot more credence to this answer).
'me'+'phis'='mephis'
'm' going within 'mephis' is 'MEMPHIS'.
(Other definitions for memphis that I've seen before include "City of Tennessee/Egypt" , "Largest city in Tennessee" , "Name of city at different times overlooking the Nile and Mississippi?" , "US city where Gracelands is located" , "Ancient Egyptian city" .)