At very low tide, something ancient begins to show just offshore from the Dip in Old Felixstowe. Most mornings, there is only sea and sky. But when the tide drops, the remains of Walton Castle appear. Fragments of a Roman shore fort built to guard the mouth of the Deben from Saxon raiders, before the sea finally claimed it. We’ve been documenting the site since early this year, heading out early — by air and by kayak to record what appears from the shore, the water and above. With help from local historians, museum records and drone photography, Walton Castle can now be documented in ways that weren’t possible before.

Every tide is different. Some mornings only a few stones appear; other days, entire sections begin to emerge.