The most popular ones are: Wikitude, Layar, Metaio, Aurasma and Augment . Wikitude delivers the Wikitude World Browser for free, which is an augmented reality web browser application, and the Wikitude SDK (software development kit) for developers, which is free for educational projects. However, the educational version of the wikitude SDK always displays a splash screen and the wikitude logo. The wikitude browser presents users with data about their points of interest, which can be the surroundings, nearby landmarks or target images, and overlays information on the realtime camera view of a mobile device. Augmented reality learning activities can be realized with the wikitude SDK. The wikitude SDK can be used to display a simple radar that shows radar-points related to the location based objects. It is also possible to recognize target images and superimpose 2D or 3D information on top of them. The developer can also combines image recognition and geo-base augmented reality. However, the building of these capabilities using the wikitude SDK requires programming knowledge.