Many Web3D sites do not offer sufficient assistance to (especially novice) users in navigating the virtual world, find objects/places of interests, and learn how to interact with them. This paper aims at helping the Web3D content creator to face this problem by: (i) proposing the adoption of guided tours of virtual worlds as an effective user aid and (ii) describing a novel tool that provides automatic code generation for adding such guided tours to VRML worlds. Finally, we will show how the tool has been used in the development of an application concerning a 3D computer science museum. Categories and Subject Descriptors I.3.6 [Computer Graphics]: Methodology and Techniques – Interaction techniques. I.3.7 [Computer Graphics]: ThreeDimensional Graphics and Realism – Interaction techniques H.5.1 [Information Interfaces and Presentation]: Multimedia Information Systems – Artificial, augmented, and virtual realities. General Terms Design, Human Factors, Algorithms. Keywords Navigati...