Hippos in Trafalgar Square

Excavations for buildings in central London have repeatedly turned up interglacial river gravels containing hippopotamus, straight-tusked elephant, lion and rhinoceros — most famously beneath Trafalgar Square. Britain's Pleistocene fauna swings between this and the mammoth-and-reindeer assemblage of glacial phases, sometimes within a few thousand years. Notably, some of these warm intervals show no evidence of humans at all: Britain was colonised and abandoned at least nine times.