The Palaeogene era, from 65 to 23 million years ago, was to radically alter the land which would become north-eastern Northern Ireland in an explosive fashion.

Our landmass was at the epicentre of an event which would see North America eventually pull away from Europe after 400 million years of being joined with it.

At this time, we were in the same latitude as present-day France.

The boundary between the North American and European plates lay to the west of Ireland. As the plates moved away from each other the North Atlantic Ocean started to form leading eventually to today’s 3000 mile separation between America and Ireland.

During the early Paleogene period, the Earth’s crust became stretched and thinned along this line.

Fissures opened up, and huge flows of lava erupted through them to flood the landscape.

For two million years, the Earth would send magma seeping far into underground faults and fissures: where this erupted on surface a large lava plateau was formed.

Successive flows of lava hardened into a pile of layers some hundreds of feet thick and whose edge today stretches from Belfast Lough and around Fair Head to Lough Foyle.

The larger fissures, through which the lava flowed, can be clearly seen as bands of dark rock which cut down the cliff faces and jut out to sea.

The columns of the Giants Causeway were formed midway through this active volcanic period in County Antrim.

The molten rock which formed them, as lava, was about 1100 degrees centigrade.

As it cooled and formed basalt, the rock shrank and cracks ran across its surface and down through the depth of the lava pond.

Meanwhile, cooling also happened from the bottom up, as the lava lay on cooler rocks from a previous flow.

The intersecting cracks produced as the lava gradually cooled led to the formation of the hexagonal columns for which the Giants Causeway is famous.

Had the cooling been at a perfectly even rate, the intersecting cracks should all have formed six-sided shapes, but cooling varied so there are also five sided, as well as four, seven and even eight sides.

However, on the Earth the hexagonal columns of the Giants Causeway are not unique and similar formations are found at the Devil's Tower in Wyoming, in the Sierra Mountains in California and, much closer to home,at Fingal’s Cave on the island of Staffa in the Hebrides off the west coast of Scotland.

Common to the names of those sites is the association with the words 'devils' or 'giants.'