Carlos Coste has created a new Guinness world record for freediving, after swimming 150 metres through a cave using no apparatus. The Venezuelan was armed with only a torch and a monofin - a single giant flipper worn on both feet - when he made the death-defying dive. The 34-year-old soared through a passage inside Dos Ojos, a colossal cave network that twists for 31 miles under Yucatan, Mexico.