At the moment there are about 3.5 million divers in Europe, of which 1 million travel solely for that purpose, according to Ilias Papaioannou, general secretary of the Panhellenic Association of Professional Diving Centers and Schools. Just four years ago, the number of overnight stays by divers from all over the world in Greece numbered 900,000, despite the hostile legal framework. He said that at a diving park near Barcelona, 15 businesses opened within the space of two years. According to recent estimates, there are about 400,000 divers in Greece. The most popular diving destinations are Turkey, Egypt and Spain. Greece is at an advantage because it has set higher safety standards, while underwater visibility is up to 30 meters, compared to just 10 meters in Spain.