Underwater City On Mars

2267, August 13th: A Scion Empire Martian scientific survey team makes a discovery on the north polar ice cap of Mars; Weeks of seismic activity led the team to launch an investigation. By sending in divers with an UUV, they were able to document evidence of a submerged city beneath the polar ice caps. Because of Mars being in its summer season, carbon dioxide ice evaporated, revealing the water ice layer and access ways to a previously unknown underwater sea that contained the submerged city. More analysis by the Scion Empire scientist indicates the city has the same technological fingerprint as previously discovered Firstborn archaeological sites.