A heat wave sweeping South Korea turned the World Scout Jamboree into a nightmare this week as over 600 attendees became sick with heat-related illnesses, officials said Thursday. The situation at the quadrennial event—billed as the world’s largest youth camp—has deteriorated to the extent that dozens of military doctors and nurses are being sent in to provide medical support. Around 43,000 people traveled from all over the world to the southwestern North Jeolla province for the get-together, which has sweltered under daily temperatures of about 95F. On the very first night, organizers said they had to respond to around 400 cases of heat exhaustion by setting up a makeshift hospital in the campgrounds. Chief Scout Bear Grylls, the British adventurer, shared a video on Instagram of him sweating profusely as he spoke at the jamboree. “It’s hot,” Grylls captioned the clip. “Look out for each other please.”