Ghosts of the ice age are being resurrected in Norfolk. When the ice sheets retreated at the end of the last ice age, mounds of ice called pingos remained underground until they thawed and the soil slumped, leaving behind shallow hollows that filled with water.
These turned into swampy wetland habitats rich in plants and wildlife and Breckland, in Norfolk, became pocked with hundreds of these pingo pools, although many of them were later filled in for farmland and became lost.
