Visit to Hagia Sophia This ancient basilica, built by Constantine the Great in the 4th century and reconstructed by Justinian in the 6th century, is one of the architectural marvels of all time. Topkapi Palace The great palace of the Ottoman sultans from the 15th to the 19th centuries housing an exquisite collection of cyrstal, silver, and Chinese porcelain, robes worn by the sultans and their families, the famous jewels of the Imperial Treasury, miniatures, the Holy Mantle; enshrining relics of the Prophet Mohammed. SULTANAHMET IMPERIAL MOSQUE Across from St. Sophia built in the 16th century by the architect Mehmet, is known as the BLUE MOSQUE because of its magnificent interior decoration of blue Iznik tiles.