In celebration of International Microorganism Day 2019 IBBS members in Portugal, Romania and Mexico organised half day meetings around the topic during which they and other members contributed to a portfolio of images on the theme of microorganisms involved in the formation of biofilms. Follow this link – International Microorganism Day 2019 – to access the portfolio, including “The Good, The Bad and The Ugly” of Microorganisms Involved in Biodeterioration and Biodegradation.