The European Championship is under way after a year-long delay, with the action taking place across Europe.
A total of 11 venues are in use for the tournament, with 51 games over the course of the month.
Conditions will vary between cities, with the likes of Glasgow's Hampden Park and Copenhagen's Parken Stadium likely to see different conditions to the Olympic Stadium in Baku or Seville's Estadio de La Cartuja.
Players' fitness is likely to be a concern after a compacted season due to the coronavirus pandemic, with substitutes crucial for every side.
Countries are able to name 23 players for each matchday from their 26-man squad, but how many subs can they use?
Here's all you need to know.
How many subs sides can use at Euro 2020?
UEFA announced that teams will be allowed to use a maximum of five substitutes at Euro 2020.
UEFA’s Executive Committee agreed in March to adjust the current rules in line with the temporary amendment introduced to Law 3 of the IFAB Laws of the Game.
In an official statement, UEFA said: "As the reasons for the five-substitutions rule remain valid against the background of national and international football calendars affected by the Covid-19 pandemic and given that the rule is already in place for the World Cup qualification matches that will run from March 2021 to March 2022, it was decided to extend the amendment to UEFA EURO 2020 in June/July 2021, the UEFA Nations League finals in October 2021 and the UEFA Nations League relegation play-outs in March 2022.”