With a reputed population of 18 million, swelled by recent arrivals from the Anatolian interior and the Middle East, this rich source of European civilisation has layer upon layer of historical associations, from the founding of the city in the 7th century BC through the expansionist Ottomans - defeated at the Siege of Vienna - right up to Turkish Independence and the city's re-emergence as a cultural and financial powerhouse.
In antiquity Istanbul's name was Byzantium, before the Emperor Constantine re-created it as New Rome, later becoming Constantinople after his death. Signs of this history are dotted across the city - the Basilica Cistern, Topkapi Palace and the Blue Mosque provide a mere sample of what's on offer.
There is nowhere like it anywhere in either Europe or Asia, indeed Istanbul is the only metropolis on earth that spans two continents.
Littered with ancient monuments, astoundingly beautiful mosques and a surprising number of art galleries, Istanbul has enough sites to keep any visitor occupied for weeks.
However, the city is also home to a thriving cafe culture amid its labyrinthine smaller streets, and each of the numerous districts has its own distinct character. Exploring these is part of the charm of visiting Istanbul, and can provide a welcome break from the inevitable crowds at the ever-popular main sites.
Istanbul is a large, sprawling and exceptionally hilly city, so it is essential to wear comfortable shoes during your stay here as you will inevitably do a fair amount of walking. Each area can easily be explored on foot, but for travelling between the areas there are a number of different options available: trams, metros, ferries, funicular railways, buses and of course the city's numerous taxis.