This is one of the most Instagrammed waterfalls on the planet.

Yesterday, the aurora borealis, also known as the northern lights, hovered above Skogafoss waterfall in Skogar, southern Iceland, as it began to freeze.

According to legend, Prasi Porolfsson, the first Viking settler in Skogar, buried a treasure chest filled with gold behind the waterfall. Through the years, many tried to lift the chest without success.

An attempt by several men to haul the chest up with a rope through a ring on the end of it ended in failure as the ring became unfastened.

The chest vanished into the depths, and all they had left was the ring, which they took back to Skogar - so the story goes.

The ring was fitted to the doors of churches that were eventually demolished, and was sent to the Skogar Folk Museum, where it now sits as one of the treasures of the museum's collection - and as a veritable testament to the power of legend.