Conversion of non-Muslim places of worship into mosques
Conversion of non-Muslim houses of worship into mosques began during the life of Muhammad and continued during subsequent Islamic conquests and under the Muslim rule. As a result, numerous Hindu temples, churches, synagogues, the Parthenon and Zoroastrian temples became mosques.
Lots More here, documenting how Muslim Architectural Triumphalism continues:
http://en.wikipedia.org/wiki/Conversion_of_non-Muslim_places_of_worship_into_mosques
Don’t forget Dome of the Rock on Temple Mount in Jerusalem.