Major buildings and landmarks in each world, including locations where adults can work and where children and teens can attend school, are represented by rabbit holes, which can be interacted with but cannot be looked into by players.
Worlds are open for Sims to explore, and Sims can be controlled even when not on a lot. The Sims 3 introduced the concept of an expanded 'open world.' Especially early in the development of the game, these were called towns, as they were much larger and more complex than the neighborhoods of the previous games.
