The City was designed with the atmosphere of European-style buildings and lighting in mind.
The City is a decently-sized quaint town built in a blocky hill landscape with layered soil, colored in different shades of brown and green grass on top of the hills (similar to Green Hill Zone). The City is placed alongside a lake or river, with multiple islands housing several buildings near the main city area. There is also a long, narrow bridge colored red (which resembles the Golden Gate Bridge) that goes all across the city, helping pave roads to get to other islands inaccessible by walking on land.
Following Eggman's devastation on the City, the location was turned into an all-out warzone, with various Death Egg Robots and Badniks scattered throughout the City, running amok. Property damage is seen no matter what section of the City is shown, with patches of fire randomly spread in the City and brimstone crashing down.
After receiving word from Rouge about a strangely positioned Eggman base, Shadow traveled through an Eggman Empire-occupied section of the City on his way to his rendezvous point with E-123 Omega. As Shadow was progressing through the CIty, he heard via intercom that Omega was being attacked by an elusive enemy, Infinite, somewhere near the location.
In Sonic Forces, when Eggman finally began his plan to take over the world with the help of Infinite, he began his conquest by attacking the City. Tails, along with several civilians, were among those who were cornered by Eggman and several Egg Pawns before Sonic arrived to fight back against Eggman. However, Infinite, alongside replicas of friends and foes of Sonic's managed to subdue Sonic, leaving a void in the world that allowed Eggman to conquer the planet.
Several months of warfare in the City would pass before the Avatar, after an attempt to fight back against a powerful Infinite, would flee from the City, which led to them joining the Resistance a couple of months later. About six months after Sonic's defeat, Tails was repairing a broken down-Omega among the ruins of the City when he was ambushed by a Chaos replica. However, Classic Sonic arrived through a portal from another dimension to save Tails, who was relieved that another Sonic was present to help fight against Eggman.
Eventually, the Resistance needed someone to go inside the City to rescue civilians when the Eggman Empire broke into Park Avenue, but with the majority of the Resistance's fighters preoccupied with other fights across the globe, Knuckles was forced to send in the Avatar to help turn the tide and save the civilians, to which the Avatar was successful at doing so. Later, Sonic would return to this location after hearing word that Shadow was leading Eggman's army against the Resistance in the City. Wanting to get to the bottom of why Shadow had aligned himself with Eggman, he encountered Shadow while the Eggman Army continued its attack on the City, only for it to be revealed as a replica created by Infinite after the real Shadow arrived and defeated the imposter. Amy Rose would later report that Metal Sonic was spotted nearby the City, to which Sonic and the Avatar joined forces to travel to the location and fight the metallic menace, who was also revealed to be a replica.
After Eggman and his empire was defeated, Sonic and the Avatar returned to the City, admiring the view and contemplating on what they were going to do now. Sonic, like always, decided to go on his own way, giving one last fist bump to the Avatar before departing.