Our internationally funded research project 'OPTIMUM' officially ended on 30th June after 3 ½ years full of exciting challenges, groundbreaking innovations and outstanding collaboration. To celebrate the joint successes and the whole consortium in an appropriate manner, our 'Project End Party' took place online on 15th July. In the hours we spent together, we clinked glasses to OPTIMUM across national borders, brought our cultures closer to each other and deepened personal friendships. Even though our project soon will no longer require activities and contributions, we as a consortium will preserve the very special 'OPTIMUM feeling'.