The biggest star on show at the tournament, three-time World Player of the Year Cristiano Ronaldo, touched down in France on Thursday as Portugal became the final team to arrive.
Fresh from scoring the winning penalty as Real Madrid won the Champions League two weeks ago, Ronaldo dispelled doubts over his fitness with two goals in a 45-minute cameo as the Portuguese thrashed Estonia 7-0 in their final warm-up friendly on Wednesday.
After France and Romania open proceedings, the newly expanded 24-team tournament kicks into gear with six games on a star-studded weekend.
England’s prolific new strike partnership of Premier League top-scorer Harry Kane and Leicester City title-winning hero Jamie Vardy will hope to outgun Russia in Marseille on Saturday.
In an indication of why the match has been designated high risk by French authorities, around 250 England fans clashed with police outside a bar in Marseille on Thursday night.
Police used teargas to break up the disturbances.
Also in England’s group, Real Madrid’s Gareth Bale will headline Wales’ opener in their first appearance in a major championship since the 1958 World Cup.
The play Slovakia, also making their first appearance at the finals.
On Sunday, Germany open their campaign against Ukraine, and Bayern Munich’s Polish striker Robert Lewandowski will aim to spoil Northern Ireland’s Euros debut.