Green Hill Zone

Green Hill Zone was the first stage in Sonic the Hedgehog (1991) for Sega Megadrive and Sega Master System. It had loops, slopes and a large dimension (perfectly fitted for Sonic's speed).

In Super Smash Bros. Brawl
In a recent trailer, Sonic was seen running in Green Hill Zone from the Sonic (universe). It similiar to the 3D model that was used for Sonic Adventure 2: Battle. It appears to be a stage as seen in leaked screenshots. It has not been confirmed by Nintendo.