Cos4Cloud (Co-designing Citizen Observatories Services for the European Open Science Cloud), a European project on technological innovation in citizen science, organizes a webinar during the citizen science month to discuss the concept of citizen observatory. As well as present opportunities and challenges of citizen observatories in the age of global change and crisis such as COVID-19. When? On 28th of April, 15-16 pm (CET) Where? Virtual webinar via Zoom