“Roman concrete” was used as building material during Roman Imperial times for a great number of famous constructions with different functions. Well-known examples are aqueducts, for example the Pont du Gard in France and the Aqua Alexandrina in Rome, and numerous monuments such as the famous Coliseum and Pantheon in Rome. While visually less apparent today, ancient harbors also were an important part of constructions supporting the power of the Roman imperial system and were invaluable to control the Mediterranean Sea trade. The article “Unlocking the secrets of Al-tobermorite in Roman seawater concrete” by Jackson et al. (2013) describes the investigation of several extremely interesting samples drilled from 2000-year-old Roman maritime concretes in 11 harbors along the Mediterranean coast [the ROMACONS project 2002–2009 (Oleson et al. 2004)].