Black Wall

"There, the dragonlords raised the famous Black Walls; seamless, fused dragon stone, two hundred feet tall, and so thick that six four-horse chariots can race along the battlement side by side, as they do each year to celebrate the founding of the city."

- Varys

The Black Walls are large walls surrounding the innermost part of the city of Volantis. The only people allowed to dwell within them are scions of the Old Blood descended from Old Valyria, and none can enter without an express invitation from them.

The Walls were formed from dragon stone by the dragonlords of Valyria when they first built the city, and are so large that on the annual celebration of its founding six four-horse chariots race along the battlements side by side.

In the books
In the A Song of Ice and Fire novels, the Black Walls are a two hundred foot high oval of fused black stone in "Old Volantis", the eastern half of Volantis.

Along with Lys and Myr, Volantis was ruled for two generations by triarchs within the Black Walls, but this came to an end when the "tiger" faction of the triarchs attempted to conquer Tyrosh and were defeated by a coalition.

Within the Black Walls exists a labyrinth of palaces, courtyards, towers, temples, cloisters and cellars. Those who dwell behind the Walls worship the old gods of Valyria, as opposed to R'hllor who is worshipped by both slaves and freedmen outside the Walls. Women of good birth who live behind the Walls are allowed to vote.