4 Best Sights in The Sea of Marmara and the North Aegean, Turkey

Juxtaposing simple form, inspired stone carving, and spectacular tile work, this mosque is among the finest in Turkey. Work on the building was completed in 1420, during the reign of Mehmet I Çelebi (ruled 1413–21). Its beauty begins in the marble entryway, where complex feathery patterns and calligraphy are carved into the stone; inside is a sea of blue and green İznik tiles. The central hall rests under two shallow domes; in the one near the entrance, an oculus sends down a beam of sunlight at midday, illuminating a fountain delicately carved from a single piece of marble. The mihrab (prayer niche) towers almost 50 feet and is covered with stunning tiles and intricate carvings. On a level above the main doorway is the sultan's loge, lavishly decorated and tiled.

The primitive mosaic floor is believed to date from the church's construction in the 6th century, during the reign of Justinian. The church was later reconstructed in the 11th century, after an earthquake toppled the original edifice. A faded fresco of Jesus, Mary, and John the Baptist at ground level on the north wall and some rather poorly preserved frescoes in the domes on either side of the apse date from the Byzantine era. In a controversial move, authorities converted this former museum into a mosque in 2011. Try to arrange your visit outside of prayer times, when you can explore the site freely and take photographs.

The daughter of Sultan Yıldırım Beyazıt built the Emir Sultan Camii in 1429 for her husband, Emir Sultan, and it sits amid cypresses and plane trees on a quiet hilltop overlooking the city. The single-domed mosque was badly damaged in the 1855 earthquake and almost totally rebuilt by Sultan Abdülaziz. The two cut-stone minarets are considered great examples of rococo, and the assemblage faces an attractive courtyard that houses the tombs of Emir Sultan, his wife, and their children.

Bursa's most important mosque dates from 1399, when Sultan Beyazıt had it constructed after vowing to build 20 mosques if he was victorious in the battle of Nicopolis in Macedonia. He ended up compromising: this one huge mosque has 20 domes. The interior is decorated with an elegantly understated display of quotations from the Koran in fine calligraphy. The fountain, with taps on the sides for ritual washing before prayer, is inside the mosque rather than outside the entrance—an unusual feature. Avoid visiting at prayer times, when Ulu Cami draws huge crowds.