Why should I go? Istanbul is among the most underrated cities for a whirlwind weekend: Europe with an Islamic elegance. Mosques bubble on the horizon. Great marine waterways, edged in evergreen, carve it with striking slashes of Mediterranean blue. It’s riven dramatically east/west by the cobalt Bosphorus, coursing south. Istanbul comes with an addictive nerviness: in spring, you can carouse in bars that spill onto side streets seemingly borrowed from Barcelona, party on a waterfront to rival Sydney’s or explore relics of empires Byzantine and Ottoman, just four hours’ flight from the UK. Your orientation starts here.

What do I do? Pay homage to the city’s spired icons, which squat like monster crabs on the skyline. Watermelon-pink and many-domed, Aya Sofya (Tue-Sun, 9.30am-4.30pm; £3.65) has survived earthquakes and empires, Crusader rape and reincarnations (Christian, Islamic, secular). It is 1,500 years old, and the dark galaxy of its interior still hums with magical mystery, pricked by sunlight from high windows. Sultanahmet Camii, aka the Blue Mosque (daily, 8am-noon, 1-3pm, 4-6pm; donations), is a shapely Ottoman triumph. Completed in 1616 by a genius apprentice to Sinan, Turkey’s “great architect”, it is identified on the horizon by its six slender minarets. Within, loud Iznik tiles gleam in greens and marines, hence “Blue Mosque”.

The rambling lawned residence of the sultans, Topkapi Palace (Wed-Mon, 9.30am-5pm; £3.65), could take a day if you idle over every spoil. Silver trays gifted to Suleyman the Magnificent; doors inlaid with mother-of-pearl for the Baghdad Pavilion; reliquaries (hair, tooth, dust) of the prophet Muhammad; and chambers of thrones, daggers and ancient porcelain from China, sent precariously down the Silk Road, via Jeddah, up the Nile and over the Med from Alexandria.

See the European and Asian shores of the Bosphorus unfurl, red-roofed and resinously leafy, on a ferry from Eminonu quay to the fishing village of Anadolu Kavagi (returns £3.65).

Disembarking, you might eat grilled shrimp and drink rosé in the nononsense Baba restaurant, as parents dip toddlers’ toes in the briny, then ascend to the ruined castle.

Or day-trip to Buyukada (returns £2.60), one of the Princes’ Islands, an hour into the sea of Marmara. Here, overthrown Byzantine rulers and nobles were once deposited. A steep, stony path, up through umbrella pines, disgorges you beside the monastery of St George of the Bells. A glass of the monks’ wine complements a perfect moment.

Back in town, sunset means margaritas at Nu Teras (June-Sept, Mesrutiyet Caddesi 145-7), a Miami-modish diner, roofless atop a tall apartment block — take a stool to survey Sultanahmet’s minarets beyond. Like that? You’ll love Leb-i Derya (Kumbaraci Is Hani 115-7), a late bar high on a roof above a tumbling central side street. South, you glimpse Topkapi, the Blue Mosque and Aya Sofya, sodium-lit and shrunk like mantelpiece ornaments. North, the endless city twinkles like a biblical Manhattan.

Where do I stay? Four Seasons Hotel Istanbul (00800 6488 6488, www.fourseasons.com; doubles from £265) trounces all the competition in tourist-thronged Sultanahmet. Based here, you’ve got historic atmosphere (it was once a prison), calm luxury, quiet courtyard dining and those must-see mosques practically ensuite. For pseudo-sultans, Les Ottomans (00 90 212-287 1024, www.lesottomans.com; doubles from £648) is an opulent marriage of chandeliers, drapes and day beds in a 10-suite mansion. Design-hotel devotees favour the Bentley Hotel (291 7730, www.bentley-hotel.com; doubles from £89), near the stores of uptown, upmarket Nisantasi. It’s a nine-storey number in a palette of cocoa, slate and gunmetal.

Where do I eat? Mikla (Mesrutiyet Caddesi 167-85; 293 5656; mains from £16) typifies fashionable nocturnal Istanbul. Crowning the high-rise Marmara Pera Hotel, it comes with slimline Scandic furnishings; and, as you dine on fish gingered up exotically, the mosque-blistered old city glitters way below. Changa (Siraselviler Caddesi 87-1; 249 1348; mains from £10) delivers Istanbul’s original and best fusion (calamari with spicy lemon and garlic sauce) in a high-ceilinged town house off Taksim Square. Or, for trad piscatorial, try Balikci Sabahattin (Seyit Hasan Kuyu Sokak 50; 458 1824; mains from £9): citrus-drenched sea bass at tables in a cobbled backstreet, with lanterns splashing vines with light overhead.

How do I get there? Both British Airways (0870 850 9850, www.ba.com) and Turkish Airlines (020 7766 9300, www.thy.com) fly to Istanbul from Heathrow. EasyJet (www.easyjet.com) flies from Luton. Trailfinders (0845 058 5858, www.trailfinders.com) has flights from Manchester with Turkish Airlines, and from Glasgow, Bristol and Cardiff with KLM via Amsterdam.

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