In conjunction with the 2002 Ars Electronica Festival, Hidden Worlds1 was installed as the first permanent exhibition based on mixed reality technology. The following year, the Ars Electronica Futurelab collaborated with Prof. Hirokazu Kato (Osaka University, Japan) to expand on this research effort and developed Gulliver’s Box2 for the 2003 Ars Electronica Center Exhibition. This set-up is also a multi-user mixed reality system, and one that has been confronting visitors from wide variety of backgrounds on a daily basis ever since. From its very inception, Gulliver’s Box was conceived as an experimental platform on which new interfaces and approaches to interaction could be tested in a laboratory setting as well as in actual use with the general public. But in spite of the installation being a prototype, Gulliver’s Box developed into one of the top attractions at the Museum of the Future. Furthermore, the experience derived from this exhibition context led to insights that have made a key contribution to the work the Ars Electronica Futurelab is doing. Motivated by this success, staffers took another long look at the concept and expanded it in several directions. Probably the most important new feature designed into Gulliver’s World is that users are no longer limited to preset environments and characters; instead, they are called upon to design the artificial world and its components themselves. This was accomplished by the development of intuitive editors with which the environment can be totally revised and customized anew each time. In dealing with the individual interfaces, users are introduced into mixed reality environments on different levels of interaction.