Mosques, mansions and markets: Turkey's biggest city has plenty to intrigue the weekend visitor. Twenty years since he first prescribed the perfect 48 hours there, Simon Calder returns

Why go now?

The vast city where Europe extends a tentative hand to Asia is easier to reach than ever, with a daily direct flight from Dublin. Get there before the crowds arrive for Istanbul's year in the sun as European capital of culture 2010.

Touch down

Turkish Airlines (01-844 7920; thy.com) flies every day from Dublin to Istanbul. Return fares start from about €215, including taxes and charges. Flight time is four hours, and the local time is two hours ahead of GMT. On arrival in Turkey, Irish passport holders must pay €15 (in cash) for a 'visa' stamp in your passport.

From Atatürk airport, 20km west of the city centre, a train/tram combo gets you swiftly and cheaply into town. At the airport follow signs for the Hafif Metro; buy a 1.50 lire/YTL (66c) token and take the train to Zeytinburnu station, about halfway to the centre. Transfer to the tram (different token, at the same price) which heads first to Sultanahmet (1), then Sirkeci railway station (2), then crosses to the newer parts of town.

Sabiha Gokcen is about 50km east of the centre, across the Bosphorus on the Asian side. An airport bus (0090 212 518 0354; istanbulairportshuttle.com) runs to and from central hotels for €7-€10, depending on the number of passengers.

View a PDF map of Istanbul here

Get your bearings

The Bosphorus, connecting the Black Sea to the world, bisects not just the city but the continents of Europe and Asia. Almost everything of interest is concentrated on the European side -- notably in Sultanahmet, with the beautiful Aya Sofia (3) and Blue Mosque (4), and the expansive complex containing Topkapi Palace (5). 'Old Istanbul' is separated from the newer area to the north by the broad inlet of the Golden Horn. It is crossed by Galata Bridge (6), which leads north to Galata Tower (7) and the hub of the new city, Taksim Square (8).

Check in

Sultanahmet, Sirkeci and Eminonu have plenty of hotels. At the Orient Express (9), at 34 Hüdavendigar Caddesi (0090 212 520 7161; orientexpress hotel.com), I paid €156 a night (including an 11pc cash discount) for a large room, with breakfast. It is a comfortable place with a superb roof terrace. Among the budget options in 'tourist valley', between Aya Sofia (3) and the water, is the reliable Side Hotel (10) at 20 Utangac Sokak (0090 212 458 5870; sidehotel.com), which has double rooms without baths for as little as €35.

To escape the crowds, and enjoy an Asian aspect to your trip, try the A'jia Hotel (11) across the Bosphorus in the suburb of Kanlica (0090 216 413 9300). Irish Independent readers can enjoy two nights for the price of one here: two nights in a waterfront deluxe room costs €389; breakfast is an extra €15 per person. Book through Mr & Mrs Smith at independent.co.uk/ mrandmrssmith.

Take a view

Valide Han (12) is a vast 17th-century trading complex buried in the middle of the busy commercial district, and an enthralling place -- a warren of warehouses and workshops around a courtyard where merchants' camels were once stabled. Soon after you wander through the gateway, a 'guide' is likely to appear from the shadows and invite you to step through a passageway on to the roof, revealing a spectacular 360-degree view of the city. Tip YTL5 (€2.23) for a brief visit.

Window shopping

Just south from here, the Grand Bazaar (13) now forms a vast and entertaining tourist attraction, rather than somewhere to find bargains, and is probably more rewarding as a place to sip tea amid a retail frenzy rather than to flex your bargaining skills for carpets or gold; you will be no match for the local traders. The market opens 8.30am-7pm daily, except Sundays.

A less overwhelming experience can be had at the Spice Bazaar (14), lined with stalls and exuberant vendors. Colourful spices are on sale, along with a million varieties of lokum (Turkish Delight).

Lunch on the run

Inside the Spice Market's northern entrance, a staircase leads up to Pandeli (15) (0090 212 527 3346), started a century ago. It opens lunchtimes only (closed Sundays) for good but pricey fare in spectacular surroundings. Try to get a seat by one of the windows looking down into the market. At the other end of the price spectrum, Tahtakale Kokorec (16) at 2 Sabuncuhan Caddesi (0090 212 519 7847) is a cheap and cheerful kebab shop, with an upstairs salon where you can relax above the retail crowd.

Take a hike

Start a long afternoon walk where the Orient Express train finished its trans-European journey; Sirkeci station's (2) bleak mid-20th-century exterior conceals some fine original flourishes, and a small but fascinating museum devoted to the pioneers of the 'Ottomanische Eisenbahnen' that connected Istanbul to the rest of Europe. It opens 9am-12.30pm and 1pm-5pm from Tuesday to Saturday; free.

Cross the Golden Horn on Galata Bridge (6), offering sublime views and good fishing (the restaurants on the lower level sometimes fry the catches of the anglers above). It leads to the Galata quarter, which, for a couple of centuries, was a colony of Genoa.

The Art Nouveau Camondo Stairs (17) are a much later addition. Climb them and you are close to the Galata Tower (7), which began life as a lighthouse 1,500 years ago but was replaced by the Genoese in 1348 with this 62m-high stone tower. Between 9am and 8pm you can pay YTL10 (€4.45) for the lift (and a short staircase) to the top for fine views across the city.

From Galata Tower, continue north to the start of Istiklal Caddesi, the pedestrianised main thoroughfare for the city. It ends at Taksim Square (8), where you can board a vintage tram for the ride back to the start of the street.

An aperitif

On the curve of the Golden Horn as it joins the Bosphorus, you'll find plenty of waterside cafés (18). Or aim for one of the rooftop terraces, such as the Imbat Restaurant atop the Orient Express Hotel (9). A beer costs just YTL5 (€2.23) here and the food is excellent if you want to linger.

Dining with the locals

Finding an innovative venue in the Sultanahmet area has always been tricky. But the recent opening of Khorasani (19), at 39 Ticarethane Sokak (a lane off the main drag of Divan Yolu; 0090 212 519 5959; khorasanirestaurant. com), offers a sophisticated Anatolian alternative to the tired, touristy offerings. It is also vegetarian-friendly. The YTL18 (€8) mezze makes an excellent starter for two, while grilled dishes are prepared on a large range near the entrance. Finish with künefe (like honey-soaked Shredded Wheat with melted cheese).

Sunday morning: go to the mosque

Creations of two of the world's leading religions confront each other at opposite ends of Sultanahmet Square. Start at Aya Sofia (3), the Byzantine Emperor Justinian's sixth-century celebration of Christianity. A millennium later, when Constantinople fell to the Ottomans, it became a mosque. After the Turkish Republic was proclaimed, it was turned into a museum in 1935. The mosaics are the main attraction; ongoing renovations the main detraction. It opens 9am-5pm daily, except Mondays; YTL15 (€6.68).

A millennium after Justinian built the Aya Sofia, Sultan Ahmet trumped it with the mosque named for him, but which is better known as the Blue Mosque. Non-Muslims are welcome to visit (via the right-hand courtyard) for free outside prayer times; you can turn up with a good chance of getting in at 9am-12.15pm, 1.15pm-4.30pm and 5.40pm-6.30pm. On Fridays, the only space is 11.45am-2.30pm.

Out to brunch

After such spiritual sustenance, repair to the Pudding Shop (20) at 18 Divan Yolu (0090 212 522 2970; pudding shop.com; 7am-11pm daily) for sweet or savoury nutrition washed down with ayran -- the yoghurt drink popular with locals. The Lale Restaurant (as it is officially known) was a cardinal point on the hippie trail to Kathmandu.

Take a ride...

... to Asia. One reason for the Pudding Shop's (20) success was that it is within easy walking distance of the Eminonu ferry quay (21), from where boats shuttle to several ports on the Asian side of the Bosphorus (flat fare YTL1.50/ 67c). Choose Kadikoy if you want to see the Selimiye Barracks where Florence Nightingale was based (if you want to see her museum, you have to visit from Monday to Friday at 11am, having sent a fax to 0090 216 310 7929), or Haydarapasa if you prefer to visit the majestic station that takes travellers into the Orient.

Cultural afternoon

Take a walk in the park to the Topkapi Palace (5), built by Mehmet II in 1459 to mark the ascendance of the Ottoman Empire. Its fine pavilions reflect the dominance of the sultans over Europe and the Middle East until the 19th century. Open 9am-5pm daily except Tuesdays; YTL15 (€6.60). Once inside you must buy a separate ticket (YTL12/€5.28) to visit the Harem -- the highlight of a visit.

The icing on the cake

The Basilica Cistern (22) is a well-hidden treasure: the entrance to this magnificent temple looks like a WC. But the YTL10 (€4.46) admission fee is rewarded when you descend into a chamber built 1,500 years ago by the Emperor Justinian -- a water tank fed by aqueducts far from the city whose ceiling is supported by more than 300 marble columns. Imagine an underground football pitch. It opens 9am-5.30pm daily.

The Independent

- Simon Calder

Irish Independent