Spagonia

Spagonia is a stage from Sonic Unleashed and Rooftop Run belongs here.

Sonic Unleashed
Spagonia makes its debut in this video game known as Rooftop Run.

Sonic Generations
Spagonia reappears in its day counterpart where both Sonics go and restore Rooftop Run.

SEGA Superstars: The Movie
Sonic, Tails, AiAi, Gum, Pudding, NiGHTS, Reala and Shinobi visit this place to meet Alex Kidd.

Trivia

 * In SEGA Superstars: The Movie, a word saying Rooftop Run is seen in Tails' book.
 * Shadow claims in the film he never visited Spagonia, yet in the scrapped multiplayer mode, Shadow can be seen.
 * Is 35 miles away from Angel Island.