Al-Aqsa Mosque ( Distant Mosque) (Arabic: المسجد الاقصى, translit: al-Masjid al-Aqsa), is an Islamic mosque on Temple Mount in the Old City of Jerusalem. It is adjacent to the famous Dome of the Rock; they form part of the platform "Al-Haram ash-Sharif" or "Noble Sanctuary" (Temple Mount). This mosque is the third holiest site in Islam after "Masjid al-Haram", a mosque in Mecca, and "Masjid al-Nabawi", a mosque in Medina.
The Temple Mount contains also the holiest site in Judaism.
Dome of the Rock and Al-Aqsa Mosque.
After the Crusaders captured Jerusalem in 1099, Al-Aqsa was used as the royal palace of the Crusader kings, then as the headquarters of the Knights Templar in 1118. The legacy of these European occupants remains in the Romanesque central bays of the main facade. 
Main facade and dome.