The subject of this paper are metal foams. The introduction elaborates on the beginning of metal foams and their development through history. The notion of metal foams and their comparison with naturally porous materials are also explained. The following describes the matter and structure of metal foams, and thus the distribution of metal foams with open and closed cells. Nine procedures for the production of metal foams are listed and explained, and are supplemented by figures and diagrams. The paper describes the mechanical, thermal and electrical properties with the stated values of some of the most important properties. Also, a comparison between cellular materials similar to metal foams such as ceramic and polymer foams is given. An overview of the application of metal foams in certain industries is also given. In conclusion, the whole paper is summarized with the most important facts about metal foams and their possible future.