United States students whose parents serve at Avianto Air Base in Avianto, Italy, live in many different villages in this region of northern Italy. Due to the varied geological conditions in which students live, a wide range of radon levels exists in the homes. In this activity, students investigated radon levels in the air of buildings. This project, called "Project Radon," allows students to experience first-hand the process of inquiry, collaboration, and communication, as well as problem-based learning and the nature of science.