Sultanahmet packs the Roman and Ottoman layers into a few hundred metres: Hagia Sophia faces the six-minaret Sultanahmet Camii across a garden, Topkapı Palace holds the headland behind, and the Basilica Cistern and Hippodrome sit two minutes away. The Grand Bazaar opens into sixty-odd covered lanes and shuts on Sundays; the Spice Bazaar at Eminönü trades daily.

Past that core the ground tilts. Fener and Balat rise from the Golden Horn in rows of painted timber houses, past the Patriarchate and the red-brick Phanar Greek College, with a shore ferry at both piers. Opposite, Galata climbs from Karaköy to the Genoese tower of 1348 in fifteen steep minutes, or the Tünel funicular of 1875 does it, leaving İstiklal Caddesi level to Taksim. Twenty minutes by boat reaches Kadıköy on the Asian side: flat walking in Moda and Bahariye. The Theodosian land walls run 6.5 km from Yedikule to Ayvansaray, three to four hours over broken ground.

Weather is kindest in May, early June and mid-September into November, 15 to 22 degrees; high summer is humid, winter wet and windy. Listed tours mostly last four to seven hours, introductions nearer two and a half. Nearly every route crosses cobbles and worn marble steps, so grip beats looks. In a working mosque, shoes come off, legs stay covered, women wear a lent scarf, and interiors shut to visitors at prayer times and around Friday midday. Ask the host which museum tickets are covered, who pays ferry and tram fares, and where the walk begins.