When a Royal Navy ship crosses into the Arctic, the crew carry out a traditional 'blue nose' ceremony.
But what does it involve and why do personnel do it?
A Navy tradition, the 'blue nose' ceremony sees sailors get their noses painted blue when their ship passes into the Arctic Circle.
An 'Order of the Blue Nose' certificate is also awarded to the sailors making their first crossing of the polar region.
It is not just the personnel that mark the occasion with blue painted noses – after crossing the Arctic Circle, it is tradition to paint a ship's bullring blue, showing it has passed 66.56° north.
The US Navy also has a ceremony to mark a sailor's maiden voyage into Arctic waters.
Personnel must complete an obstacle course before an audience with Boreas Rex, the King of the North, who decides if their frozen quest was a success by marking them with a blue nose.