Atlantis

Atlantis is the name of a Terran colony orbiting the star Sirius. The planet itself was entirely covered by water, enabling the construction of New Atlantis, the only above-surface city on the entire planet. Several refugees from the Igaaren-Yann war were brought to Atlantis. There were many fights in the city between the Igaaren and the Yann in the years of conflict. When the war ended, the Igaarens and Yann learned to live peacefully, opposing treatment of the Yann when they were conquered.