This $1 specimen stamp from Niuafoʻou (Kingdom of Tonga) celebrates the centenary of the world-famous “Tin Can Mail” service. The design features a vintage map of the volcanic island of Niuafoʻou, also known as “Tin Can Island,” where mail was uniquely delivered by swimmers through shark-infested waters in sealed tins. Issued as part of a commemorative series, the overprinted “SPECIMEN” indicates a non-postal sample distributed for reference or collectors. The pale turquoise background with bold magenta and black inscriptions evokes a classic cartographic style.