Located in the center of the capital city of Poseidonis, the royal palace was the tallest and most extravagant building in the entire city. This was the home of the reigning monarch, his family, entourage and council elders. Over the years, the palace has known many rulers including the King Trevis, the interim ruler King Pletus, the corrupt King Thesily, King Orin and Lord Vulko.
When a species of sentient giant jellyfish took control of Atlantis, they used the throne room as their primary base of operations. Aquaman led a resistance cell against the invaders and killed them by releasing poisonous gas into the palace. 
During this time, Mera, driven insane by the death of her son, fought against her husband Aquaman and was nearly killed in the throne room when Aquaman accidentally impaled her upon an upturned piece of metal. 
A short time later, the Atlantean Royal Palace was destroyed when Oumlandian nuclear submarines bombarded Poseidonis with torpedoes, destroying the great dome. The palace was subsequently rebuilt. 
- Orin the First