Istanbul · 3 Days

Built in 537 CE by the Emperor Justinian, the Hagia Sophia was for nearly a thousand years the largest enclosed space in the world and the supreme achievement of Byzantine architecture. Its dome — 55 meters above the marble floor, resting on a ring of forty windows that flood the interior with light — was an engineering feat not surpassed for centuries. Now operating as a mosque, the building retains its layered character: Byzantine mosaics (some partially covered, some visible), Ottoman calligraphy medallions, and the worn marble columns of a structure that has been adapted, rebuilt, and loved by successive civilizations. The interior acoustics, especially during the call to prayer, are extraordinary.

The Sultan Ahmed Mosque — known as the Blue Mosque for the 20,000 hand-painted Iznik tiles that line its interior — stands directly across the Hippodrome from the Hagia Sophia. Built between 1609 and 1616, it is the only mosque in Istanbul with six minarets, a fact that caused considerable controversy when it was built (six minarets had previously been reserved for the mosque at Mecca). The interior is suffused with a cool blue-green light from the stained glass windows, and the geometric patterns of the Iznik tiles reward close looking. The courtyard, with its central fountain and graceful arches, is one of the most beautiful in the city and less crowded than the mosque interior.

For four centuries the administrative heart of the Ottoman Empire, Topkapi Palace is less a single building than a city within the city — a series of courtyards, pavilions, and gardens spreading across the tip of the historic peninsula above the confluence of the Bosphorus and the Golden Horn. The view from the fourth courtyard, where the Bosphorus, the Asian shore, and the Sea of Marmara are all simultaneously visible, is among the finest in Istanbul. The palace museums contain the imperial treasury (with the Topkapi Dagger and the Spoonmaker's Diamond), a remarkable collection of Iznik ceramics, and the Harem complex — the private apartments of the Ottoman imperial household, open to guided tours. Allow enough time; most visitors underestimate the scale.

One of the world's oldest and largest covered markets, the Grand Bazaar has operated continuously since 1461. Its 4,000 shops spread across 60 covered streets selling carpets, gold jewellery, leather goods, ceramics, spices, textiles, and antiques. The main corridors near the entrances are tourist-oriented; the best strategy is to walk toward the center and the outer rings, where the merchants are more relaxed and the goods more varied. The hans (caravanserais) within and adjacent to the bazaar — Sandal Bedesteni, Büyük Valide Han — are worth finding for their architecture alone. Bargaining is standard; the first price is never the final price, and a polite "çok pahalı" (too expensive) opens most negotiations.

The Galata Tower was built by the Genoese in 1348 as the tallest structure in the city, and it remains one of Istanbul's most recognizable landmarks — a cylindrical stone tower rising above the rooftops of Karaköy with 360-degree views from its gallery. The view from the top takes in the Golden Horn, the Historic Peninsula with its domes and minarets, the Bosphorus, and on clear days the Asian shore and the Princes' Islands. The neighborhood around the tower's base has been colonized by cafés and boutiques in recent years, but climb the steep lanes above it — Galata proper — and you find a quieter, more residential character with independent galleries and old apartments.

İstiklal Caddesi — Independence Avenue — is 1.4 kilometers of pedestrianized boulevard lined with bookshops, music stores, cinemas, and the ornate 19th-century arcades that are the street's hidden treasures. The historic tram still runs its length. But the real Beyoğlu is in the passages and backstreets: Çiçek Pasajı (the Flower Passage, a Victorian arcade now filled with meyhane restaurants), Nevizade Sokak (a narrow alley lined wall-to-wall with traditional meyhane serving raki and meze), Çukurcuma (the antique and vintage district one street behind İstiklal), and the quieter residential lanes of Cihangir, where the creative class lives and the Bosphorus views from any hilltop are remarkable. Walk the full length of İstiklal, then spend time in the backstreets.

Karaköy — the former warehouse district at the foot of Galata Tower, directly on the Golden Horn — has become one of Istanbul's most interesting micro-neighborhoods in recent years. Specialty coffee roasters, design studios, small restaurants with daily-changing menus, and galleries have moved into the old commercial buildings without entirely displacing the original ship supply shops and wholesale hardware stores that gave the area its character. Walk the waterfront toward Eminönü: the Galata Bridge, where fishermen line both sides casting into the Golden Horn and boats below serve grilled fish sandwiches directly from their decks, is a working institution that has operated in this spot for well over a century.

The shore walk north from Beşiktaş through Ortaköy is one of the finest urban walks in Istanbul. Ortaköy itself clusters around a neo-baroque mosque sitting directly at the water's edge beneath the first Bosphorus Bridge — one of the city's most photographed scenes. The square behind the mosque fills with waffle vendors and tea gardens on weekends. From Ortaköy, continue north along the waterfront path through Arnavutköy — a neighborhood of wooden Ottoman houses leaning over the narrowest point of the strait — to Bebek, where the cafés along the water have exceptional Bosphorus views and the fish restaurants are excellent. Alternatively, take the public Bosphorus cruise from Eminönü for a 90-minute view of the city from the water.

Kadıköy's market district — a dense grid of streets just inland from the ferry terminal — is the best food market in Istanbul, and it operates at full intensity every morning. The fish hall (Kadıköy Balık Pazarı) opens early with the day's catch laid out on ice; surrounding it are cheese and dairy shops, olive vendors with dozens of varieties in brine, spice merchants, pickle shops, bakeries selling simit and börek, and fruit stalls. The surrounding streets of Moda and Caferağa extend the market into independent bookshops, vintage clothing stores, and wine merchants. This is where the city's residents — not tourists — shop for their daily food, and the atmosphere is completely different from anything on the European side.

Moda is the quiet residential neighborhood south of Kadıköy, and it is one of Istanbul's most pleasant places to walk. A grid of streets lined with late Ottoman apartment buildings slopes gently toward the water; the ground floors contain corner bakeries, small neighbourhood restaurants, secondhand bookshops, and the kind of independent cafés that don't need Instagram to fill their seats. The Moda pier, at the southern tip of the neighborhood, has a small seaside park and a tea garden where the view across the water — the Hagia Sophia dome, the Blue Mosque minarets, the Topkapi walls — is entirely unobstructed. Sit here long enough and the ferry traffic on the Bosphorus becomes a kind of meditation.

Üsküdar — a short bus or dolmuş ride north of Kadıköy along the Asian shore — is a different register entirely from the creative bustle of Moda and Kadıköy. More conservative in character, more Ottoman in its built fabric, Üsküdar has one of the finest collections of imperial mosques outside the Historic Peninsula. The Mihrimah Sultan Mosque (designed by the great Ottoman architect Sinan for the daughter of Suleiman the Magnificent) sits on the waterfront square where the ferries dock; its slender minaret and graceful proportions repay careful attention. The shore promenade north toward Kuzguncuk — a former Jewish and Greek neighborhood with painted wooden houses and an unusually well-preserved character — is a lovely afternoon walk.

The Kız Kulesi — Maiden's Tower, or Leander's Tower in some traditions — is a small lighthouse and tower on a tiny islet in the middle of the Bosphorus, a few hundred meters off the Üsküdar shore. It has served as lighthouse, Byzantine watchtower, Ottoman quarantine station, and filming location, and has been an Istanbul symbol since antiquity. The tower can be visited by boat from the Üsküdar shore (short boat trips run regularly from the waterfront). But the finest experience is simply watching it from the Üsküdar or Salacak waterfront promenade at dusk or after dark, when it is floodlit and reflected in the water, with the lights of the European shore behind it. This is one of Istanbul's great views, and it is entirely free.