Istanbul is one of the best cities in the world for a layover because the Istanbul Airport (IST) is a major global hub with excellent transit links. If your layover is at least 6 to 10 hours, you can take a taxi or the M11 metro line into the city center. In 2026, the most popular activities include visiting the Sultanahmet district to see the Hagia Sophia and the Blue Mosque, which are architectural marvels. You can also explore the Grand Bazaar, one of the oldest covered markets in the world, to shop for spices, lanterns, and Turkish delight. For a shorter stay, a Bosphorus sunset cruise offers a relaxing way to see both the European and Asian sides of the city without getting stuck in heavy traffic. If you are flying with Turkish Airlines and have a layover between 6 and 24 hours, you may even be eligible for their "Touristanbul" service, which provides a free guided sightseeing tour including transportation and meals, or their "Stopover" program which offers a free night in a 4 or 5-star hotel depending on your ticket class.