This is the 100th issue of Microbial Cell, wich has been releasing monthly issues since January 2014. The cover depicts a composition of all published covers in the course of these more than 8 years, in which Microbial Cell has published more than 400 scientific articles. For credits regarding the single covers, please refer to the original cover information; image generated by MIC. The cover is published under the Creative Commons Attribution (CC BY) license.