As a former high pressure biochemist, I have to note the passing of a great pioneer in deep sea research. Jacques Piccard, who died on Saturday aged 86, was one of only two men who reached the very bottom of the oceans, the Challenger deep, Mariana Trench, some 11 km below sea level. The hydrostatic pressure down there is around 1,100 bar (rule of thumb: 1 bar for every 10 meters), so you want to be extra sure that your equipment is pressure-proof. It has often been remarked (and is probably still true today) that we know more about the far side of the moon than about the bottom of the ocean. So it is fitting that a lot more people have visited the moon than the mariana trench.
Trivia alert: Jacques Piccard's father, Auguste Piccard, who also went very deep into the oceans and very high into the atmosphere, is believed to have been the inspiration for the character of Professor Calculus (Prof. Tournesol in the French original) in the Tintin cartoons.