Our seas and oceans are substantially polluted by conventional and chemical munitions from the two World Wars. They were introduced by different pathways e.g. mine laying, naval battles and shipwrecks. However, the biggest amount originates from large scale ammunition dumping activities after World War II. The goal of the OpenSource based Ammunition Cadastre Sea is therefore data acquisition, assessment and monitoring of the status of ammunitions in our seas and oceans and their effects. Almost all relevant data in this field has a spatial context. Therefore the idea is capturing, visualizing and analyzing everything that is related to ammunition in the sea (e.g documents, maps, high-resolution measurements) and combine everything by spatial relationships. In addition, a key component of the Ammunition Cadastre Sea are European research projects e.g. DAIMON or North Sea Wrecks. DAIMON (Decision Aid for Marine Munitions) uses for example artificial intelligence to analyze complex situations and provides recommendations for actions.