What is a Danish "Efterskole"?

The efterskole is a special Danish boarding school for students between 14 and 18 years old. Each year about 28.500 students attend one of the 260 "efterskoler" here in Denmark. 

The "efterskole" is also for international students. Each student has to pay a school fee to attend an "efterskole". Watch a video about the "efterskole" here.