The project at hand involved the introduction of a new subject in upper-secondary grammar school, "English for the natural sciences", and all the staff training, professional/organisational development, and evaluation measures associated with it. Our utmost aim has been to enable students to acquire the skills necessary to follow and actively take part in scientific discourse carried out in English, and thereby "broaden their mind", i.e. allow them to discover, see and be aware of the European and international dimension of their classes. In addition, the subject should prepare them linguistically for further and/or university-level studies in the natural sciences or areas related to them, especially if the medium of instruction is solely English. In order to provide for effective teaching and student satisfaction with their new subject, it was vitally important for the staff member developing and teaching the subject to attend a professional development course centring on the improvement and acquisition of specialised skills (e.g. in methodology, curriculum/syllabus design, materials development) in CLIL (Content and Language Integrated Learning). NILE, an acknowledged provider of teacher training courses located in Norwich, England, provided a two-week intensive course called "CLIL for Secondary Teachers" in summer 2014, which focused on exactly those competences the teachers of "English for the natural sciences" need. One member of staff, a motivated and resourceful teacher who is one of the creators of this new subject at our school, took part in this course in England. Following the training placement in Norwich, there was a feedback talk with the Head of School about the skills gained, and in September 2014, "English for the Natural Sciences" started for the very first time at our school. The methodology used follows the traditions of CLIL and English across the curriculum, i.e. student-centred, involving innovative teaching methods and making use of new technologies. Pair and group work as well as preparing and giving presentations are key elements of this new subject. Continuous evaluation and assessment of the project and its results have been carried out in the form of questionnaires, competence/skill checks, staff meetings and formal student assessment. In this context, student as well as teacher feedback seemed fundamental in developing the project further. The student's abilities, their skills and competences have been the best proof of the success of the project and its results respectively. Their motivation and readiness to use English in professional contexts and their improved knowledge of vocabulary, specific grammatical structures and text types enables them to pursue studies or a career in the area of or related to the natural sciences - not only in Austria, but also in Europe or other countries in the world. The project's long-term effects are obvious: Apart from offering our students the opportunity to get a European or international perspective of what they are learning at school, we also encouraged other staff members to try out CLIL in their subjects, which has extended the students' knowledge of specific vocabulary also to other professional and academic fields. Additionally, the course at NILE has enabled our colleague to provide (internal and external) training sessions for staff members who are interested in using English as a medium of instruction in other subjects as well. Furthermore, the success of this project triggered even more active organisational development at our school, which includes the introduction of other new subjects or the use of innovative teaching methods in traditional subjects. Another aspect of organisational development is internationalisation, which has undoubtedly been furthered by this project. Networking among professional experts and starting new school partnerships are only two of many positive effects that "English for natural sciences" and the preparatory teacher training course in England have had.