Route 99

Route 99 (ルート99) is a city-type level that appears in Sonic Advance 3 as well as the second episode of Sonic X. It lies on the outskirts of, presumably, Central City and the still active Station Square respectively. It appears to be a highway near the city. It has 3 acts, a boss fight, and a special stage.

Boss
The boss here starts off with a fight with Gemerl. To defeat him, you need to hit him two times. (The first time you play this boss, it is four times.) Then you go to fight with the Egg Hammer. To defeat it, you need to know when he's going to hit you. The hammer will smash left and right alternatively. When Dr. Eggman smashes down, you need to smash his face in! You need to hit him six times for him to be destroyed.

Trivia

 * The city background of this level appears to be based on a pre-2001 Lower Manhattan as a skyscraper that resembles the North Tower of the former World Trade Center complex (as well as other buildings that resemble the surrounding World Financial Center) can be seen amongst the skyline. The original building was destroyed in the September 11th Attacks, nearly 3 years before Sonic Advance 3's release.