I mean, Helen's given a little potted history, but can you sort of explain why we're seeing them more now than we seem to have ever done in the past?

Yeah, and Helen has given a very good description there and in a previous podcast as well about the heatwave, a really clear explanation of what happens when a site is buried, lost, flattened at ground level, unless it reappears clearly, particularly when you see it from the air or on internet aerial photographs like Google Maps or from a drone.

But everybody, you know, in their gardens will have old paths, concrete paths, old flower beds, maybe that have been covered up in the last 40 years.

In a dry summer, those concrete paths are going to part from wither the grass and appear as yellow lines, a bit like we have with Roman roads or the walls of Roman villas and Roman forts.

And then deep ditches dug around prehistoric farms or pits where people used to bury their rubbish.

Those dug through subsoil will react as well in a drought summer.

So crops, wheat, barley, even grass, growing over a deep pit when the rest of the subsoil is pretty stony or clay, that'll show up as a dark green mark in that grass.

Presumably most of the time you've absolutely got to get up into the air.