Travelers visit the ancient city of Istanbul to tour the Blue Mosque and the Byzantine Hagia Sophia, and to shop at the Spice Bazaar and the Grand Bazaar, one of the largest and oldest markets in the world. Topkapi Palace, once the home of the Ottoman Sultans, features displays of weaponry, porcelain, art, and fabrics in a beautiful example of architecture. Exploring Istanbul’s neighborhoods, restaurants, shops, and museums are more visitor favorites.