Petnica Science Center is the biggest and, probably, the oldest independent nonprofit organization for extracurricular science education in SE Europe. Since 1982, Petnica has organized more than 3,500 programs (seminars, workshops, research camps…) for nearly 65,000 students and science teachers in 15 disciplines of science, technology and humanities. Majority of programs are designed for secondary-school students although there are many programs for primary-school pupils, university students and science teachers. Main conception of Petnica activities is the model called Learning through Reserach (similar to Inquiry Based Science Education in regular schools). Attendants of regular Petnica programs are coming from all countries of former Yugoslavia and all these courses are being realized in Serbian language. However, Petnica occasionally organizes programs (like PI) in English for international participants.