ArenaNet showing the Capitol city of the Asura called Rata Sum.
See the updated Asura page here: http://bit.ly/qevHzR
The greatest physical example of asuran magical mastery is their mighty city, Rata Sum. Starting with no more than a set of scattered ruins belonging to a failed race, the asura erected a testament to their power. Now dominating the surrounding area, Rata Sum is a huge floating cube riddled with interior passages, its upper reaches divided into smaller cubes.