Rocks are the building blocks of our dynamic planet and the foundations of European culture and civilization. They form the landscape and provide us with valuable resources. Rocks to a geologist are like a map to a traveller. They provide clues to its past from which certain conclusions can be drawn and predictions can be made. Hidden in rock, there is a multitude of treasures to be discovered: minerals, metals, crystals and fossils. Man’s first tools were made from stone, rock was quarried and mined to build tombs, memorial or runic stones, houses, fortresses, aqueducts, bridges, roads and amphitheatres. Partners embarked on a journey of their regions in search of rock formations, mining villages and historical, man-made stone constructions with the purpose of exploring, developing and celebrating the links between that geological heritage and all other aspects of the area's natural, cultural and social history. Their findings have been uploaded to our common Wikispace.. Together, we learnt how to read geological maps, how to classify rocks and minerals, discovering their properties as well as their geological history. Hence, our field work took us to European geosites and ecomuseums and allowed us to meet and interview experts whose professions involved working with rocks, stones or minerals. Our trails were registered with a GPS, with descriptions of nearby budget accommodation, photos, videos, environmentally-friendly activities and uploaded to the collective Wikispace as examples of Ecotourism/ Geotourism.Science and humanities teachers collaborated constantly in creating innovative, multidisciplinary CLIL science lesson plans.All communication was carried out in English.The four partner schools that hosted work meetings went to great lengths to reveal not only their geological and cultural treasures but also their great sense of hospitality. Learning about rocks has led us to a collective appreciation of, and respect for, Planet Earth.