Pre-order the Engineer III Endurance 1917 Chronometer at a limited-time price: shop.ballwatch.ch/e1917. On their expedition, Shackleton and his crew persevered through 17 hours of darkness every day. For extreme readability in the darkest environments, the timepiece features 1mm high micro gas tubes, alongside cold temperature resistance oil and anti-magnetic protection to 80k A/m. Available with or without mechanical thermometer module. Special offer ends 23 August 2017. Pre-order now: shop.bal

Sharks have been cast as the ultimate villain ever since the movie “Jaws” was released 50 years ago this summer. The film tells the story of a great white shark terrorizing beachgoers, but in reality, humans pose the greater threat to sharks. Endurance swimmer Lewis Pugh is swimming around Martha’s Vineyard, where “Jaws” was filmed, to get that message out. PBS News’ Ali Rogin spoke with Pugh for more. | PBS NewsHour