You won't spot them from the ground - but the recent dry spell and some stunning new aerial photographs have revealed hidden medieval features in the Powys landscape.

New pictures released by the Royal Commission on the Ancient and Historical Monuments of Wales(RCAHMW) show long-buried hill-forts and settlements, whose outlines have been revealed by the parched landscapes of Mid-Wales.

A statement from RCAHMW said: "The unprecedented spell of hot, dry weather across Wales has provided perfect conditions for archaeological aerial photography. As the drought has persisted across Wales, scores of long-buried archaeological sites have been revealed once again as ‘cropmarks’, or patterns of growth in ripening crops and parched grasslands.

The Royal Commission’s chief aerial investigator Dr Toby Driver has been busy in the skies across mid and south Wales over the last week documenting known sites in the dry conditions, but also discovering hitherto lost monuments.

Dr Driver says conditions for aerial photography are the best he's ever seen since joining the organisation.

"I’ve not seen conditions like this since I took over the archaeological flying at the Royal Commission in 1997.

"So much new archaeology is showing it is incredible.

"The urgent work in the air now will lead to months of research in the office in the winter months to map and record all the sites which have been seen, and reveal their true significance."

But the organisation, whose role is to promote the archaeological, built and maritime heritage of Wales, say they face a race against time to get the sites photographed before the weather breaks - and the crop markings disappear again.

"With the drought expected to last at least another two weeks Toby will be surveying right across north and south Wales in a light aircraft to permanently record these discoveries for the National Monuments Record of Wales, before thunderstorms and rain wash away the markings until the next dry summer," they added.

The new information will be stored in the National Monuments Record of Wales, which already homes over 500,000 aerial photographs

If you want to find out more about RCAHMW you can visit their website