Fingal's Cave is on Staffa, an island near Scotland.
The island, like many of the Inner Hebrides, is made of volcanic rock.
The vertical lines seen in the photograph were formed when hot lava cooled.
The shrinking lava produced a columnar pattern.
These volcanic rocks date from around 50 to 60 million years ago.
At that time, the North Atlantic was starting to form, with Europe beginning to split from North America.
This diagram shows how volcanoes began to separate Europe and North America 60 million years ago.
Magma from deep in the Earth moved upwards and was erupted at the surface.
Volcanism has continued ever since along a structure called the Mid-Atlantic Ridge.
It created the Atlantic ocean floor and is still pushing the continents steadily apart at a rate of around 2.5 centimetres a year.
In Iceland, this steady volcanism has interacted with a hot mantle plume to create the volcanic island we see today. (Image: © Elizabeth Pickett)