This paper describes the Gesture Mouse system recently developed at the Visual Information Processing Laboratory of the University of Florence. This system allows users to explore and select information displayed on large wall panels using their hands as pointing devices. Graphical interface operation is the same as with standard mouse-based computer interfaces; the main points of concern interaction style, and in particular naturality and usability issues. First of all, unlike both traditional and more advanced yet intrusive human-computer communication contexts, users do not have to wear or otherwise use any extra hardware device to carry out interaction: they just have to point to an area of interest in the wall panel with their own hands. Secondly, while a traditional mouse must lay and be operated on a flat 2D surface such as a table, Gesture Mouse allows users to move freely in a 3D, real-life environment such as a room. Last, but not least, pointing in 3D is an everyday life operation, which therefore does not require a priori skills or training. Fig. 1 shows an example of natural interaction in a museum room augmented with computer infrastructure, where the user can inspect electronically-displayed paintings and have access to hypertextual information related to them by a "click" operation. Users can issue Gesture Mouse clicks by pointing persistently on a selectable screen area for at least two seconds: this time-related selection modality makes the system reproduce the behavior of a one-button mouse.