Devon's capital city is built on an ancient volcano.
This jaw-dropping fact shines a light on the prehistoric age of Devon where violent, lava-spewing volcanic eruptions altered its landscape forever.
Volcanoes in Devon were active in Permian times, 285 million years ago, a time apocalyptic change which spanned 47 million years.
In the hilly bits of Exeter and its surrounding towns the remains of these mighty volcanoes can still be seen, with their lava flows found within sedimentary layers of rock.
A fascinating example of this can be spotted near the Mill on the Exe on Bonhay Road: An entire ancient river bank exposed underneath Mount Dinham.
Basalts, the most common form of volcanic rock, can also be found clearly cropping out of the ground around Rougemont Castle in Exeter city centre.
That's because the castle, constructed by William The Conquerer to safeguard his rule from rebellious Exonians in late 1060s, is built on a volcanic vent.
A perfect home for Normans who had brought blood and fire to the county.
The funnel of lava from the vent, forming a volcanic cone, supplied the tough but difficult stone that built the landmark - appropriately named in French 'Red Mountain'.
It's not just Exeter city centre where traces of Exeter's violent natural past are unearthed.
Nine small outcrops of minette and lamprophyres can be found between Pinhoe and northern Exeter.
But why was Devon the scene of such catastrophic natural change? The movement of earth's tectonic plates is directly to blame.
Millions of years ago, Devon was an arid desert sat at the heart of a continent near the burning hot equator and teetering on the edge of two sections of the earth's crust.
Exeter History
Volcanoes formed when these sections collide and melted.
For more about Exeter's ancient past read our account of Isca Dumnoniorum, Roman Exeter.
