Macross City

Macross City - Earth

 
In 1999, the massive ship that became known as the  SDF-1 crashed to Earth, cleaving through an island in the South Pacific.  As the ship was investigated, a city sprang up on the island to support the various personnel.   
 

Macross City - Space

 
On launch day, the alien race that became known as the  Zentraedi attacked and Captain Henry Gloval was forced into using its untested Space Fold System.  The results were...unpredicted.  Instead of arriving at the moon, their intended target, they ended up somewhere near Pluto.  Also, they managed to carve out the bulk of Macross City and bring it with them, along with a good chunk of land, ocean, and even atmosphere.   It was the beginning of the First Robotech War.
 
The instant freezing of the ocean water over the city managed to preserve atmosphere and pressure, so the residents didn't immediately die, and the Captain soon had the joy of re-relocating 70,000 civilians inside his ship.  As the ship had been originally designed for a full military compliment of the giant  Zentraedi, and the ship only had a crew of about 800 humans, there was plenty of room not only for the people, but their buildings as well.  Most of the city itself was salvaged and rebuilt inside the cavernous ship. 
 
The civilians integrated well to ship life, although things got a little tense when the ship had to transform to use its massive Reflex Cannon.  Still, they opened and successfully operated restaurants, bars, clothing stores, and even arcades.  It soon became the main recreational facility for the military crew.  As the SDF-1 underwent its painful, long journey home, the civilians even began such events as a Miss Macross Pageant, and created a movie studio, producing its own feature films. 
 
Once the SDF-1 finally reached Earth, it was to an unwelcome surprise.  The aliens were only interested in the ship, not Earth itself, and none of the regional governments were interested in bringing such trouble on themselves by welcoming the refugee civilians.  Finally, Captain Gloval managed to work it out with the North American Ontario Quadrant, who agreed to take the civilians.  However, a massive battle over the Quadrant resulted in a mishap with the Omnidirectional Barrier Defense System, and a 25 mile radius of the Quadrant was utterly destroyed.  The offer to take the refugees was immediately withdrawn.  Gloval was forced back into space with all civilians on board. 
 

New Macross City

 
Eventually, the First Robotech War ended, and the crippled SDF-1 was stranded on Earth.  The denizens of Macross City, proud of their ship, built another new city around the remains of the ship, named New Macross City.  The city eventually became the new global headquarters, as much of the planet had been decimated in the last battle of the war.