Bacteria

Bacteria (Greek bakterion - rod) form one of the three basic domains into which all living organisms are now classified. They are microscopic and were first observed in 1676 by Antoni van Leeuwenhoek using a homemade microscope in water and human saliva. The largest bacterium observed to date is already visible to the naked eye and was discovered in 1999. It is thus, so to speak, the blue whale among the bacterien.