A recent heatwave has done something that years of archaeological fieldwork could not – it has pulled back the curtain on dozens of lost and forgotten ancient sites hidden beneath the Welsh landscape.
The Royal Commission on the Ancient and Historical Monuments of Wales says the extreme heat has revealed crop marks and soil patterns that expose the outlines of structures buried underground, some of which have not been visible this clearly in decades.
When the ground dries out during prolonged hot spells, crops and grass above buried features behave differently to the vegetation around them. Stone foundations and walls hold less moisture, causing plants above them to dry out faster and appear lighter from the air. Ditches and pits, on the other hand, retain more water and stay greener for longer. From above, these contrasting patterns create ghostly outlines of settlements, enclosures, field systems and burial sites that would otherwise be completely invisible.
Aerial survey teams took full advantage of the conditions, flying over large stretches of Wales to photograph and record what the heat had revealed. The results have been remarkable. Sites ranging from prehistoric enclosures to medieval field boundaries have appeared across the country, giving archaeologists a rare and detailed look at what lies beneath the surface.
Some of the sites uncovered are already known to historians and archaeologists, but had not shown up this clearly in aerial photographs for many years. Others appear to be entirely new discoveries, adding to the growing picture of just how densely settled Wales was throughout its long history.
The Royal Commission has been using these conditions to build on its existing records, which document thousands of historic sites across the country. Officials say moments like this are invaluable because they allow surveyors to spot features that ground-level investigation would simply miss. The scale of what can be seen from the air during a heatwave cannot be replicated any other way.
Wales has a rich and layered archaeological history stretching back thousands of years, and much of it remains hidden beneath farmland, pasture and moorland. Iron Age hillforts, Roman roads, Bronze Age burial mounds and early medieval settlements are all part of the story, and events like this heatwave act as a reminder of just how much is still waiting to be properly understood and recorded.
Archaeologists are urging landowners and members of the public who spot unusual patterns in fields or open ground during dry spells to report them. Photographs taken from elevated positions, drones or even upstairs windows can sometimes capture detail that proves useful to researchers.
The Royal Commission is continuing to analyse the images gathered during the recent hot weather and says it expects the findings to contribute significantly to the national record of historic sites in Wales. Full details of the newly identified locations are expected to be published in the coming months as the analysis work is completed.
For now, the heatwave that brought discomfort to much of the country has at least left behind something genuinely exciting for those interested in the deep history of Wales.
Saw something about this on the news last night, absolutely fascinating stuff. Droughts are rubbish obviously but if there’s a silver lining it’s finding out what’s been hiding under our feet for thousands of years. Wales is genuinely full of surprises innit.