beach dangers hut lifeguard lifeguard-towers lifeguards look-out lookout lookout-tower observation observe ocean prevent-drownings prevention protect protection safety scan scanning seashore shark-spotting shelter structure structures supervise supervision swimmers swimming tower volunteers watch ALS architecture Australian-Lifeguard-Service beaches coast coastal emergency-service holidays outdoor popular raised recreational-beaches rescue sand seaside shore sights surfers swimmer-rescue tourism tourist tourists traditional travelling travels water-rescue water-sport-participants