The Open Day of the Ruđer Bošković Institute (ODI), a popular science event of the RBI, was held on June 10 for schoolchildren, and online for all others interested. The live activities were organized at research stations for the following topics: chemistry, physics, biology and biomedicine, and environmental science. Doctoral students from the Tolić group Ivana Ponjavić, Isabella Koprivec, Valentina Štimac and Ana Petelinec participated in the event at the biology station. At the RBI Open Day, the Tolić Group introduced visitors to the process of mitosis and the mitotic spindle, and to better explain the research, visitors were able to look at different samples on a light microscope.