Marmara Region in northwest Turkey spans between Europe and Asia, with Istanbul the country's largest city at its heart. It's purely a geographical unit - Turkey doesn't have administrative layers between national government and its 80-some city-provinces - and in 2022 had a population of 27,050,405, a third of the national total.

A great flooded fault line sunders Europe from Asia. The west channel at Gallipoli / Çanakkale is the Dardanelles (classically known as the Hellespont), the north channel through Istanbul is the Bosporus, and between lies the inland Sea of Marmara. Together they connect the Black Sea with the Med, and if you control the channel you get to control a whole lot else. Tremors along this and related fault lines threw up mountains and hurled down cities. Its geothermal heat seared the limestone bedrock into marble - in Greek μάρμαρον (marmaron) - energetically quarried and shaped into noble buildings and statues, and so the Sea and Region of Marmara were named.

This region has been the birthplace of empires and their graveyard. Best known are the Ottomans, who emerged in Söğüt around 1300, moved on to capture Bursa then Edirne then Constantinople / Byzantium, nowadays Istanbul, and dominated the East Med region for 600 years. Their cultural descendants could be dubbed the auto-mans, as beyond city centre is a 100+ km industrial sprawl where everyone is either snarled in traffic, driving furiously, or busy manufacturing more automobiles. You need to get past this to enjoy quiet forests such as Çilingoz Nature Park on the European Black Sea coast, the many beaches, and intriguing old towns where you may be the only tourist. Motorways snake across the terrain and you can drive off from Istanbul airport to reach Gallipoli and Troy in a few hours.

Climate is mostly mild and temperate, with warm, generally sunny summers and chilly, grey and rainy winters, with much variation by altitude and distance from the sea. Hence Marmara Region has both beach resorts and ski resorts. Western visitors are generally familiar with the Mediterranean summer and regard copious draughts of beer as the antidote. They may be taken aback and unprepared for the winter, with brutal "Lodos" winds and snowfall disrupting even major highways. But to be fair, the local highway maintenance crews seem equally unprepared.

Istanbul has many English-speakers at least in its tourist sector, but elsewhere they may be hard to find. Learn some basic survival Turkish or have a translation app on your phone - preferably both.

Buses from Istanbul serve all the main towns, so any journey along a radial route is straightforward. For cross-country routes you'll do better with your own vehicle: small villages may be linked only by occasional dolmuş, and it's difficult to find reliable timetables for these, even if they bother with one.

There are no air routes within this region, and the only link on the YHT line is Istanbul to Arifiye, for Adapazarı. That leaves railway users to take the regional trains. These trundle infrequently from Istanbul to Edirne, Çorlu, Uzunköprü and Gebze, and from Bandırma and Eskişehir to Balıkesir, continuing to Izmir.

Ferries cross the Sea of Marmara from Istanbul to Bandırma and Mudanya, across its eastern inlet to Yalova, and across the western reaches between Erdek, the Marmara islands, and Tekirdağ. They also link the Princes' Islands just off Istanbul, cross the Dardanelles although there's nowadays a bridge, and sail to the Aegean islands of Bozcaada and Gökçeada. They're a pleasant way to cross the Bosphorus between Europe- and Asia-side Istanbul, though the metro is quicker.

• Ottoman capitals: Istanbul was only their third. It has a fabulous collection of architecture, but Bursa and Edirne display the earlier part of the story.
• Bridges and causeways: the Ottomans needed to carry their roads across river valleys that were not deep, but wide and dangerous in spate. They built a series of attractive multi-arched bridges-cum-causeways, some over 1 km long. Many remain in use for light traffic. There are good examples at Dilovası near Gebze, Edirne, Lüleburgaz, and of course at Uzunköprü which means "long bridge".
• Mosques are the main legacy of early Ottoman times, since they've been maintained against earth tremors and land developers. Istanbul and Edirne have the very best.
• Külliyesi is a religious complex centred around a mosque. Typically these contained a madressah (seminary), lodge, soup kitchen, hospital and caravanserai, plus a few tombs. Many have been swept away leaving only the mosque, but Gebze has a surprisingly complete example engulfed in a modern city.
• War Memorials of 1915 for the Allies and the Turks are at the south end of Gallipoli peninsula around Eceabat.
• Decorative tiles adorn many mosques and palaces. The craft was re-launched in the 17th century and is best seen in İznik, though the finest pieces have gone far away.
• Weird attractions include Darıca Hobbit Village in Gebze and Seka Park Film Set in İzmit. Dupnisa Cave near Demirköy has thousands upon thousands of bats, and that's not counting the cave you can't enter because it has too many.
• Istanbul to Izmir is a plexus of long-distance routes across this culturally-rich region.

• Mount Uludağ is a mountain resort linked by cable-car to Bursa, with hiking trails in summer and skiing in winter.
• Beaches and resorts in this region are mostly small, catering to domestic tourism: pleasant examples are along the Gulf of Saros, the Marmara island of Avşa, and the Aegean island of Bozcaada. The international resort strip starts further south beyond Izmir.
• Hot springs bubble up in many areas. The best developed spa zone is in Bursa.

• Istanbul is the only city with a cosmopolitan choice.
• Other towns offer standard Turkish fare, with limited vegetarian choice. They have neither the polyglot mix of west European cities nor an international tourist market, so they lack other cuisines such as Chinese.

• Beer, wine and rakı is served in most cafes. There are few free-standing bars outside Istanbul.
• Wine (mostly red) is grown locally, especially in Şarköy District on the Marmara coast, and on the islands of Avşa and Bozcaada.
• Rakı is no longer distilled at Tekirdağ, production has moved to the Izmir area, but there's no shortage.

Beware traffic even on back country lanes, and safeguard valuables.

The seas are not tidal, but may have stiff currents and careless boat-drivers.

• South is Aegean Turkey, with Izmir the country's third largest city, and top sights including Ephesus, Pergamon and Pamukkale.
• East is Central Anatolia, with the capital Ankara, old-world Konya, and the fairy chimneys of Cappadocia.
• Northeast, Black Sea Turkey takes in grubby Zonguldak, beach resort Samsun and faraway Trabzon.
• West you cross the border, either into Bulgaria or Greece.