World War Two was a time of huge sacrifices – including for members of a team of scientists in London who conducted hundreds of dangerous experiments on themselves to help divers and submarine crews breathe underwater.
A new book has revealed for the first time how their discoveries would pave the way for D-Day, the largest seaborne invasion in history.
Rachel Lance's book "Chamber Divers: The Untold Story of the D-Day Scientists Who Changed Special Operations Forever" details "the many injuries and near-death experiences the researchers endured, from a broken spine to a collapsed lung", said Business Insider.
John Burdon Sanderson Haldane, from the genetics department at University College London, and members of his lab became "guinea pigs", conducting experiments in hyperbaric chambers.
They had been tasked with the job after a Royal Navy submarine sank during a dive test in 1939, killing 99 people whose breathing apparatus failed to save them.
The scientists' discoveries were crucial for the success of one of British history's most significant hours. Ahead of D-Day British teams would go over to Normandy and "sink down to the bottom during the day, breathe inside their safe, enclosed environment" and then "come up at night, crawl ashore, measure the sand, measure the beach angles, provide detailed maps, everything, and then go home", Lance told NPR.
This, and the success of D-Day itself, was thanks in part to the work of Haldane and his colleagues. Their dangerous experiments not only supported the famous invasion, said Business Insider, but also "contributed to the science behind modern-day scuba diving". | 
