Form of outdoor education is that of canopy tours. These are pre-established routes that travel through woods and mountainous areas by means of zip-lines and aerial bridges that have been built in trees. Participants are attached to harnesses on a steel cable for their safety. While canopy tours have a strong history of civil and scientific use, their main purpose now is recreational and they have become a central part of the adventure tourism industry.  Hundreds of these tours exist in five continents, but countries with rainforests and jungles – like Thailand, Costa Rica, Mexico, Chile and Brazil – are the most popular. In particular, there are many of these tours in Costa Rica.However, canopy tours can also be done across Europe, North America, Australia and Africa.