Currently, mark-making practices as a form of identification and proof of life are an unrealized resource. Over a three-year period, systematic walkover surveys were conducted on and within fortifications and other structures on the island of Alderney to locate historic and modern marks. The investigations presented in this article demonstrate the importance of non-invasive recording and examination of marks to identify evidence connected to forced and slave labourers, and soldiers present on the island of Alderney during the German occupation in World War II. Names, hand and footwear impressions, slogans, artworks, dates, and counting mechanisms were recorded electronically and investigated by using international databases, archives, and translation services. We discuss the value and challenges of interpreting traces of human life in the contexts of conflict archaeology and missing person investigations and underline the need for greater recognition of marks as evidence of past lives.