Eagle City was originally founded in the Sea of Tranquility near where the Americans landed Apollo 11 in the 1900s. The first military garrison over a century later simply called it Eagle Base in honor of the Lunar Lander, and the name stuck. The first civilian colonists named it Eagle Dome, and later waves called it Eagle Colony as they built more domes on the surface or dug deep into the Lunar rock. It became Eagle City in the 2100s as it stretched its reach throughout the Sea of Tranquility. And then they made it a sea in fact and not merely in name.