If You Have Limited Time

Here is one way to plan your visit if time is limited: Start your first day off on a whirlwind, visiting the Blue Mosque and Aya Sofya to get a sense of the grandeur of the Byzantine and Ottoman empires. In the afternoon venture out of Sultanahmet to the Kariye Müzesi to see amazing frescoes and mosaics from the Byzantine era. Then check out the Grand Bazaar, where you can wander until closing time at 7 (6:30 in winter) and maybe stop at nearby Rüstem Pasa Cami for a look at the tiles. If you're staying in Sultanahmet, take an evening stroll to see the floodlit domes and minarets of the Blue Mosque and Aya Sofya.

You could spend your second morning at Topkapi Sarayi and have lunch at one of the cafés in the compound or just outside the gates so you can visit the Arkeoloji Müzesi and Eski Sark Eserleri Müzesi in the palace forecourt in the afternoon. After that, you'll have probably reached your quota of treasure- and antiquities-appreciation, so you can immerse yourself in Istanbul street life. Head to Tünel Square in the New Town, and follow Istiklal Caddesi through Galatasaray Meydani, stopping at the Fish Market and Flower Arcade, to Taksim Meydani, the center of the modern city.

With another day, you could see more of the Byzantines, descending into the atmospheric underground cistern, Yerebatan Sarayi, then ogling the exquisite mosaics in the Mozaik Müzesi. For even more evidence of Ottoman power, head to the lower Bosphorus to see Domabahçe Sarayi, the naval and military museums, and Yildiz Parki.

If you want to see the Bosphorus but don't have a whole day, either take the faster Turyol cruise, or take an evening commuter ferry to relax after a hard day's sightseeing.

If you have more time, you can enjoy Istanbul with a little leisure. Think in terms of neighborhoods: you'll want to spend at least three days in the Old City, seeing the Byzantine and Ottoman monuments, and a day heading out to the less-visited Western Districts. Plan a full day around Karaköy, Besiktas, and the New Town, and a day cruising up the Bosphorus. You won't have trouble filling additional time: maybe another look at the mosaics and frescoes at the Kariye Müzesi, then a stop to compare them with those in the Mozaik Müzesi. Or another swing through the Grand Bazaar. Perhaps a trip to the Princes' Islands. Or just wander: few cities reward walkers more amply.