In order to increase scientific literacy and the knowledge of science and technology of Europe's citizens, the European Commission suggests a more student-centred implementation of natural sciences in education systems. Inquiry-based learning (IBL) is not only an accepted method to promote students' interest and motivation, it also helps students learn the scientific method and fosters their research skills. However, IBL is rarely used in European classrooms. The main reason is that due to the strict curricula teachers do not have the time for preparation and they do not feel well equipped and trained in the use of IBL methods in class. The Photonics Explorer programme addresses these problems on the European level. Within the programme, a pan-European collaboration of professors, teachers and photonics experts have developed the Photonics Explorer kit for the teaching of optics and light-related topics in physics across various European secondary school curricula. It is designed for intra-curricular use and contains specially designed, hands-on experimental components, worksheets based on guided IBL and multimedia material. Additionally, the kit provides a teacher guide with a suggested lesson outline and sufficient background information for each topic. (Contains 3 figures.)