Beautiful, just beautiful - watch this amazing footage of 'arctic unicorns', the narwhals.
And here they are in ZENITH:
"There is no moon but the sprinkle of starlight picks out a dazzling mosaic of ice that is so fragile it shifts with the movement of the sea. And there is something else. A long, silver point is sticking up out of the thin crust of ice.
Mara screws up her eyes. It looks like a sword.
The silver sword vanishes then re-appears further in front, breaking a path through the icy waves. Another sword rises out of the ocean, surges towards the first and crosses it. Mara gasps as the swords clash then vanish.
Narwhals.
She only saw them once on Wing. Great, shell-encrusted whales, far out in Longhope Bay. Island folk legend said a speck of ground narwhal tusk a day would make you live a hundred years or more, just as the narwhals do.
A narwhal horn always points to the North Star."
Nature's Great Events: The Great Melt is on Wednesday 11 February on BBC One at 2100 GMT
