A corona passport with a QR code on a mobile phone at Rotterdam the Hague airport, Netherlands on June 9, 2021. With a corona passport (digital Covid-19 certificate), the EU wants to make free travel between member states easier. With the 'Digital Green Pass' you can show that you have been vaccinated, recently tested negative or already recovered from corona. More and more countries are going yellow for the holidays. Photo by Robin Utrecht/ABACAPRESS.COM