Archaeologists love droughts. Because once people have disturbed the soil by digging pits, that soil holds water a little better than the undisturbed soil around it. The difference is not enough to show during most years, but in a drought that severely stresses the plants, the old pits just may show up as spots where the crops are healthier. And in evening or morning light, an aerial photograph just might show you things never seen before. Like this Neolithic henge in Ireland, just found using a drone. It's in the Brú na Bóinne archaeological landscape around Newgrange, a place with many Neolithic monuments, once probably the spiritual center for one of Ireland's tribes.