Magnetotactic bacteria are aquatic micro-organisms which have the specific capacity to navigate along the lines of the earth’s magnetic field. This property is related to the formation of chains of magnetic crystals called magnetosomes. All magnetotactic bacteria synthesize nano-sized intracellular magnetosomes that are surrounded by ultra-thin bio-membranes. The magnetosome chains serve as compass for navigation of the magnetotactic bacteria, and the cell flagella are considered as the mechanism for propelling the bacteria forward. This presentation describes various functions of the architectured structure of magnetotactic bacteria as well as their possible applications in biotechnology.