New Mobotropolis is the current capital of The Mobian Federation, and is one of the biggest cities in YouTube Poop World.
Old Mobotropolis was one of the first cities in recorded history. It became the capital of the Kingdom of Acorn, until the nation was taken over by Dr. Robotnik. The city was then renamed Pingustropolis. After the Mobian Revolution, the Mobians re-captured the city but it became a toxic wasteland during Robotnik's rule. The monarchy then decided to create an exact clone of Mobotropolis and call it New Mobotropolis.
The city was initially finished in 2005, but the city soon started to grow rapidly as Mobius started to invest a lot in infrastructure.