The story begins with a tide. In May 2013, coastal erosion at Happisburgh, on England’s east coast, stripped away a layer of sediment. What it revealed was a series of hollows, pressed into ancient laminated silts. They were footprints. They looked, to the untrained eye, like puddles. But to the team from the British Museum, Queen Mary University of London, and the National History Museum, they were a cipher from a vanished world.
Dating them required a patient triangulation of methods. The geological context placed them in the early Pleistocene. Paleomagnetic analysis of the sediments showed the last reversal of Earth’s magnetic field had not yet occurred, locking the date to before 780,000 years ago. The biological evidence—the types of extinct plant and animal fossils found with them—narrowed it further. The conclusion was a quiet shock: these impressions were made more than 800,000 years ago.
They are not grand monuments. They are ephemeral, a moment of passage by a small group, perhaps two adults and three children, moving south across a mudflat near a river estuary. The maker was likely *Homo antecessor*, a species known from Spanish fossils. The prints are a negative space, a record of weight and movement and then absence. They tell us that hominins were in northern Europe nearly a million years earlier than most evidence suggested, in a climate colder than today’s Britain. They walked, and the mud held their shape for epochs, until another tide, on another day, briefly gave them back.