Don't miss the mammoth Aya Sofia, built in the sixth century as Constantinople's main cathedral and converted to a mosque 900 years later. Other must-sees include the tile-filled Blue Mosque, completed in 1617 to rival the Aya Sofia, and the opulent Topkapi Palace, home of Ottoman sultans.
For a fun excursion, take a ferry ride up and down the Bosphorus. Then hit the Grand Bazaar, a maze of more than 4,000 shops that's been in business since 1461.
For luxury in historic surroundings, try the Ciragan Palace hotel, located in a former Ottoman palace, or the Four Seasons Hotel at Sultanahmet, which occupies a former prison. Budget-minded travelers will like the centrally located Hotel Kupeli (see Resources).
Istanbul is hot and steamy in the summer and cold and occasionally snowy in the winter. That makes spring and fall the best seasons for a visit.
Istanbul has two international airports: Sabiha Gokcen International Airport, which mostly services low-cost European airlines, and the much larger Ataturk International Airport, which handles everyone else.
