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 nearly 2,200 programs (seminars, workshops, research camps…) for 45,000 students and science teachers in 15 disciplines of science, technology and humanities. Majority of programs are designed for secondary-school students although there are a lot of programs for primary-school pupils, university students and science teachers. 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.