The application of virtual worlds through Internet for teaching allows that the student can submerge himself in friendly environments that make learning more pleasant. This article presents three educational applications developed in these worlds. The first, for virtual museum of history and culture, shows a set of virtual worlds designed in VRML where the student interacts with different objects. When an object is selected, its name can be show and the student can listen to its history. In the following application, a virtual classroom, the created world can be shared simultaneously by several users. There are diverse materials available as in the traditional classrooms, for example a blackboard, laser pointer and a slide projector. Finally, the latest advances in the creation of virtual environments have been applied in the third application using a game server. This has made possible the design of a more realistic world where the student can interact with other users and share his experiences.