Mausoleum at Agra in memory of a wife (3,5)
I believe the answer is:
taj mahal
(Other definitions for taj mahal that I've seen before include "Mausoleum at Agra built in memory of emperor's favourite wife" , "Famous mausoleum in N India, memorial to wife" , "... mausoleum raised by ..." , "Famous Indian mausoleum in Agra" , "Agra memorial" .)