Asshai

Asshai is a city located on the far side of the explored world from Westeros, in the far south-east of the Essos continent. Little is known about it save that it is a great seaport and its people are exotic.

In the books
In the Song of Ice and Fire novels, Asshai is said to lie on the far south-eastern shores of the Jade Sea, a body of water far to the east even of the Free Cities and Slaver's Bay. It is located close to an enigmatic area called 'the Shadow' or 'Shadow Lands', and the city is sometimes known as Asshai-by-the-Shadow. The city is usually travelled to by ship, but it can also be reached overland by a circuitous route. The Dothraki consider the city and surrounding area to be ill-omened. The city is reputed to hold large amounts of arcane lore, including knowledge of dragons.