Istanbul in 3 days

Justinian's church of 537, the world's largest for nearly a thousand years, then a mosque, a museum from 1934, and a mosque again since 2020.

A sixth-century underground reservoir held up by 336 columns salvaged from ancient temples, with carp swimming in the water below the brick vaults.

Sultan Ahmet I's mosque facing Hagia Sophia, named for the blue and white Iznik tiles inside; its six minarets caused a scandal at the time.

The sultans' palace for four centuries: four courtyards of kitchens, treasury, the Prophet's relics and the harem, above the Bosphorus and the Golden Horn.

The city ferry company sails from Eminönü to Anadolu Kavağı near the Black Sea, or on a shorter round trip to the second bridge.

Started by Mehmet II in 1461, it now covers 61 covered streets and nearly 4,000 shops, with its own mosques, fountains and banks.

A Genoese tower of 1348, long a fire lookout, whose terrace looks all round over the Golden Horn, the old city and Asia.

Old Greek and Jewish quarters on the Golden Horn, with the Ecumenical Patriarchate, a red-brick Greek school and a cast-iron Bulgarian church from Vienna.