I Liceum Ogólnokształcące in Leszno is a state school, currently educating 619 students and employing 63 teachers. The school is doing its best to provide its students with thorough development according to the European Union standards. We offer in-school competitions, support and guide students entering national competitions and Olympiads, and frequently take part in national and international projects in order to ensure optimal conditions for students to develop and for us to self-improve. The main aim of the project and the attendance of its participants in the courses were connected with the following needs: 1. developing key competences concerning science, mathematics, IT and foreign languages in accordance with the Lisbon Strategy 2. perfecting the knowledge of English and Spanish among our teaching staff 3. developing cross-cultural competence among our teachers with the aim of making students more open, tolerant and respectful towards diversity 4. promoting the idea of lifelong learning among teachers as well as students 5. helping our graduates apply for courses at European universities The aims of our project corresponded closely with the aims of the Erasmus + scheme, which focus on building school partnership, reinforcing innovation, gaining knowledge and educational courses. Nine teachers from our school took part in the scheme. An essential criterion of choosing the participants was a variety of subjects taught ( there were teachers of English, Spanish, maths , physics and IT ), which was supposed to result in synergy and create a new kind of cooperation among the school’s teaching staff. Involving both science and language ( English and Spanish ) teachers was crucial in order to achieve the effect of integrated knowledge . Moreover, it enabled us to thoroughly grasp vital aspects of various fields of knowledge. The language teachers ( English and Spanish ) chose methodology courses whereas the science teachers opted for general English courses. All the courses coincided with the professional needs of our teachers and with the needs of the school. The abilities acquired during the above- mentioned courses definitely boosted the quality of teaching in our school, made the school more attractive locally and contributed to implementing the objectives of the project. The most important results of the project included: improving the competence of the participants, in the language courses, in the Spanish and English languages, establishing cooperation with other participants and foreign schools, improving the skills in the use of new technologies in the educational work with young people, and also increasing incentives to educational work, shaping intercultural and personal competences. Upon completion of the mobility we implemented on the school grounds, inter alia, such actions as: the introduction, in the classes of the humanities and linguistic profile, the subject called knowledge of English-speaking countries, the preparation of the remaining staff to actively participate in the Erasmus Plus projects, the continuation and development of the English language in the sciences and natural sciences classes, the introduction of a class with the extended curriculum in the Spanish language, creating, in the mathematical club and publishing on the blog, e-learning materials for students. The school's strategic development includes the achieved objectives and further develop them in the long term - we are going to enlarge our education offer in the field of CLIL in Spanish as well as in mathematics and physics, we will use innovative teaching methods e.g. geogebra or CARR and implement new complementary subjects. Thanks to such actions the students will have the opportunity to integrate the knowledge of mathematics, sciences and foreign languages.