The Vendée Globe. Said to be the toughest race in sailing. The winner 4 years ago took 78 days or so. Alone for 78 days or more. A third of that in The Southern Ocean.
They start tomorrow.
There is a nice CNN documentary on the race at this link. It is from 6 months ago, at the start of the Transat – the Trans-Atlantic race – which is the qualifier. (It includes a bit of other sailing news, but it starts and ends on the Vendée Globe.