Selmburg

Salemburg is a beautiful castle city island on the 61st floor of Aincrad in SAO. The castle's outer appearance has a white granite surface with serene spires at its center. It has green foliage throughout the city and a lake surrounding it, making it extremely beautiful when the sun is upon it. The houses on this level are extremely expensive. It is notable for having Asuna's former residence.

Sword Art Online
Kirito first appears on this floor trailing Asuna, having been invited for a dinner in her house with the S-rank Ragout Rabbit's Meat he had caught earlier. After finishing dinner, Kirito and Asuna talk about the real world and they discuss forming a party, which Kirito finally agrees to under pressure from Asuna. As Kirito didn't know how long he could stay at her house without being rude, he leaves for his house and meets her tomorrow to party with her.

Later, Kirito and Asuna goes back to her house after a tragic incident within the guild. Kirito requests to stay at her house for the night, which she allows. While in bed, Kirito ask Asuna if they want to get married. Asuna smiles and says yes. The newlyweds go to buy a house on the twenty-second floor. At first, Asuna offered to sell her house, but Kirito goes against the idea, instead collecting all their rare items and selling them to Agil to collect the money needed for the new house.

When the game is cleared, Kirito and Asuna watch as Salemburg crumbles into the clouds along with the other floors.