Millions of people are facing travel disruption over Christmas, as the surging Omicron variant sees flights cancelled and safety curbs tightened.
European government have taken new measures as a surge of COVID-19 cases swept across the continent.
In some parts, the increase has been compounded by the emergence of the new Omicron variant, first detected in South Africa.
Italy, Spain and Greece have made face masks compulsory outdoors again during Christmas.
Catalonia, in northern Spain, has imposed an overnight curfew, and the Netherlands is in a strict lockdown.
Despite early findings that Omicron is milder than other variants, scientists are concerned by the number of cases.
The UK, France and Italy reported on Thursday record infections
In the US, daily Omicron cases have risen beyond the peak of the recent Delta wave. Hospitals are filling up across the country.
Scientists believe Omicron could spread more easily than Delta. It could out-compete Delta to become the dominant variant in the UK.
But much is still unknown, and it could still take weeks to understand how severe illness from the variant is and what it means for the effectiveness of vaccines.
The World Health Organisation (WHO) warned in a new press statements about the Covid-19 surge in Europe.
