This past summer England experienced its worst heatwave since 1976. However, this heat wave had some unusual consequences: the extreme heat created “parch marks” that have helped scientists locate thousands of ancient structures and burial sites long hidden under the English countryside. These archaeological finds utilize aerial photography and global positioning system satellites. Scientists are using this data to determine the location, age, and type of archaeological sites they’ve come across.

Parch marks are caused by underground structures left by ancient peoples. Typically, the soil in those areas is rocky and difficult for plants to get their roots into. During a heatwave, when the plants start to die and turn yellow, the areas where the roots don’t have a good hold will change color first. This can create almost a perfect drawing in the grass of the structure underneath. The same is true for ancient trenches or burial sites where the roots in some spots have a better hold on the soil underneath. These drawings are often picked up by aerial photographers or hobbyists, or even satellites flying overhead and taking photos of the earth.

There are 31 satellites in the global positioning system known as GPS, and each is equipped with a highly accurate atomic clock that provides accurate data for scientists on the ground. GPS Satellites have been used for interdisciplinary science since they were first launched. More and more scientists are able to utilize satellite data to benefit their research. Whether it is measuring the rising sea level across the globe or the locations of ancient human settlements, satellites are indispensable.

GPS is relatively open access. Scientists can utilize data points in connection with other scientists. That allows for a phenomenon like the U.K. heatwave this summer to be explored by as many scientists as possible. During the heatwave, scientists had to move fast to catalog the parch marks using both aerial photography and GPS. It only takes a bit of rain to re-hide these treasured lines. Now that the color is returning to the British landscape, archaeologists are relying on GPS data gathered during July and August to find their new potential dig sites.