Astoria
Astoria was the first city created by the queen. It is where the mermaid tear pool exists. The pool that Sereia's tears were gathered and the city rose up around it. It is from this pool that the stars were created. Once a year no matter how far a mermaid roams they must return to the pool to refresh. Failure to do so will make them very sick and can result in death. Mermaids don't die of old age but can die from outside causes and being away from the sea for too long is one of them. It is hard to kill a mermaid in the water and impossible to do within the healing pool
Landraces are allowed in the city with a mermaid or with permission. They can be given the ability to breathe underwater though there are tunnels of air set up that air exists to allow those that want to visit to stop by and travel around. Some races even live and work in the city itself. Some just like to see it. So, visitors are allowed to view it through such tunnels.
The outside of the city of Astoria in the ocean. The city blends with sea life as they move around it in the backdrop.
The gate to the city one can walk the path for air breathers or swim through the top using the water paths that are open and offer a view into the sea and sea creatures access to the city.
The city has paths inside for both air and none air breathing visitors to travel to different locations and meeting room or ocean water and not with ways for both to interact if need be.