Situated in the heart of Istanbul, this gigantic mosque was built on the site of the former Church of the Holy Apostles, where most of the Byzantine Emperors were buried. When Mehmet the Conqueror built the original mosque here, the church was already in ruins. An earthquake in 1766 destroyed the first mosque, so most of what you see here today was built by Tahir Aga, the architect of Mustafa III. Remnants of the original mosque can be found in three porticoes of the courtyard, the ablutions fountain, the main gate into the prayer hall and the mihrab. Mehmet the conqueror's tomb is also here, behind the prayer hall.