Megopolis City

Megopolis City was once the capital city of the Floating Island and the centre of all echidna activity. The Zone now lies in ruin, thanks to thousands of years of neglect and decay.

Ancient Past
Megopolis was once under the control of Pochacamac and his powerful Echidna tribe. The only Zone known to exist in ancient times, the area was filled with grand buildings which were teeming with Echidna technology and history. Pochacamac's chambers were the largest, where he supposedly lived with daughter Tikal the Echidna. The city came under attack from the Drakon Empire, the aliens coming to claim the Chaos Emeralds that had been stolen from them. With the Emeralds stored in Pochacmac's building, the Great War would continue for years.

Kohenyu were also known to roam around the outskirts of Megopolis and were treated as sport and food for the echidna dwellers.

Present day
These days, Megopolis City is just another Zone that has been left to disrepair by Knuckles the Echidna. Since Knuckles has no memory of how the city once stood or how to handle the ruins without wrecking them further, he has been content to leave it the way it is. He is first seen visiting the area when rescuing Doctor Zachary from a Guardian Robot. During this fight, he damages the Zone further, punching a large fissure into the ground.

After Knuckles' World Tour of Mobius, the echidna tasked the Guardian Robots with cleaning up the Zone, using his trunk of ancient documents. The Zone was the landing spot for the Doctor Robotnik Appreciation Tribe during their mission to steal the Chaos Emeralds. However, they were betrayed by Ms Alpha and her team, leaving them to be captured by the Guardian Robots.

Sonic the Comic Online
Tikal the Echidna found herself back in the future, getting her memories erased by Ebony. Knuckles and Porker Lewis took a detour to the city while taking the Chaos Emeralds home, hoping to jog Tikal's memories of her past. While walking to the Emerald Chamber, Buddy encouraged Big the Cat to push a boulder on top of the heroes so the Drakon could become Chaos once more.

Megopolis City was also the scene of Zachary's escape attempt, capturing Tikal to give Knuckles an ultimatum.