Blue Hole, Egypt
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The Blue Hole is a favourite dive site of daredevils looking to test their mettle. North of Dahab in Egypt’s Red Sea, the sinkhole drops down to depths of around 300 feet (91m) with a notorious horizontal tunnel on its outdoor wall known as the Arch.
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The Red Sea is abundant with marine life that can be seen on shallow dives, but many explorers are lured into the depths of the Blue Hole due to its enticing reputation as one of the world’s most dangerous but beautiful dives. Most fatalities, including one of a world-renowned dive expert in 2017 (the tragic story of which was used for Netflix's acclaimed documentary The Deepest Breath in 2023), have occurred when divers have attempted to go through the Arch, which leads from the sinkhole into open water.