Adventure Field

Adventure Fields, also called Town Stages, are playable areas in the Sonic the Hedgehog series that first appeared in Sonic Adventure. They serve as the hub worlds from the various games and is where the majority of the games' story takes place. Unlike Action stages, these locations do not have a fixed goal nor a limit of time restricted for the players, but instead serve as from where the player can reach the game's different playable Stages or additional in-game features

The player is free to explore these locations. Future games also had locations that serve as Adventure Fields.

Sonic Jam
Sonic Jam was the first game to have a fully explorable, 3D location known as Sonic World. It was the selling point of the game as well as the project that would lead to the development of Sonic Adventure. Sonic World had various museums on Sonic's history as well as a giant button that dispense missions.

Sonic Adventure
The Adventure Fields of Sonic Adventure were:
 * Station Square, an urban theme coastal city.
 * Mystic Ruins, a rural theme archeological dig site with jungles and ruins.
 * Egg Carrier, a giant airship which was flying in Sky Chase. However, due to a malfunction, it fell into the ocean, but could still be accessed.

Description
It is from Adventure Fields the player can access the Action Stages. What Action Stage and its theme is varies depending on the Adventure Field. It is also in Adventure Fields the player can find Key Stones or the Employee ID Card which are needed to unlock certain Action Stages.

In Sonic Adventure DX: Directors Cut, Mission Mode was added to the game, where by approaching Mission Cards, the players are issued a challenge. The nature of each challenge varies, such as performing tasks in the Adventure Fields or somewhere in an Action Stage.

Each Adventure Field also has access to a Chao Garden, whose themes are also based after their Adventure Field, such as Station Square Garden located on the top of the hotel; Mystic Ruins Garden located by the cliffs with some ruins; and on the Egg Carrier, a teleporter that will take the player to the Egg Carrier Island.

Sonic the Hedgehog (2006)
In Sonic the Hedgehog (2006), Sonic, Shadow and Silver could explore Soleanna's Town Stages, which consist of the Castle Town, New City, and the forest of Soleanna. It was from these Adventure Fields the player can receive Town Missions from locals and find the Mirrors of Soleanna which grant access to the Action Stages.

Sonic Unleashed
Sonic Unleashed had the most Adventure Fields of any past games in the Sonic the Hedgehog series (nine in total). They were known as Town Stages in the Xbox 360/PlayStation 3 version and Villages in the PlayStation 2/Wii version, and are based on various cultures around the world. Within these stages, the player could interact with locals or obtain various items, such as food and souvenirs. In the Town Stage there would also be the access point to the Entrance Stage which serves as the true hub to the Action Stages of each region.