Odds - Title: 9/1; To win group: 4/11; To qualify: 1/33
Best European Championship performance: Winners (1964, 2008, 2012)
How they qualified
First, Group F - P10 W8 D2 L0 F31 A5 Pts26
Qualified with two games to spare, going unbeaten in their group. Dropped points in away games against the second and third-placed teams in the pool - Sweden and Norway. Indeed, they needed an injury-time equaliser to keep their unbeaten record intact in Sweden.
Despite no player scoring more than four goals, the 2012 champions still managed to find the net 31 times in qualifying, while they were also tight at the back.
Qualified for the Nations League finals by winning a group containing Germany. Finishing top looked a tough ask following a 1-0 defeat in Ukraine but a stunning 6-0 demolition of the Germans in their final match proved decisive.
Made a slightly suspect start to World Cup qualifying, being held at home by Greece before requiring a 92nd-minute winner to beat Georgia so haven't been in the dominant form of yesterday. However, that loss to Ukraine is their only one in their last 22 internationals.
With Gerard Pique having left the international stage, the door is open for Manchester City's Aymeric Laporte to come straight into the centre of the defence having only just changed his allegiance from France.
There has been no nailed-on striker for some time, Spain often playing with a 'false nine', but after a season which saw him win the Europa League, Villarreal's Gerard Moreno is pushing for a start. Only Lionel Messi scored more goals in La Liga this season. He's battling Alvaro Morata for the centre-forward role.
Man City's Ferran Torres has also been starting in attack of late - he has already won the European Championship at under-17 and under-19 level. Torres scored five goals in his last four games from the right-hand side.
However, another of Spain's rising stars, Ansu Fati, misses out due to injury.
Luis Enrique - Holds the distinction of having played for both Real Madrid and Barcelona. As manager of the latter, he won the Treble in 2014/15.
Took the Spanish job after their calamitous 2018 World Cup campaign but stepped down the following year due to personal reasons - his young daughter was seriously ill and subsequently died. Enrique returned to the job later in 2019 by which time Spain had qualified for these Finals.
While not necessarily regarded as the greatest tactician, Enrique has been lauded for his man-management and motivational skills.
Odds - Title: 100/1; To win group: 13/2; To qualify: 8/15
Best European Championship performance: Semi-finals (1992)
How they qualified
Second, Group F - P10 W6 D3 L1 F23 A9 Pts21
Finished behind Spain in their qualifying group - the pair will meet again in the Finals.
Their only loss came away to the Spaniards, while they drew home and away against third-placed Norway, whose five draws prevented them from ousting their neighbours from second spot.
Wins over Georgia and Kosovo at the start of World Cup qualifying were therefore welcome but did nothing to suggest they will be able to compete at the business end of this tournament.
Zlatan Ibrahimovic has long been Sweden's star turn but having made himself available for the national team again only recently, a knee injury means he will miss out on Euro 2020.
After scoring five goals in qualifying, Robin Quaison, of Mainz, holds claims to lead the line in Ibrahimovic's absence, as does Real Sociedad's highly-rated youngster Alexander Isak. Another of Sweden's new generation is Juventus' Dejan Kulusevski, who can play wide or in behind.
Still, this doesn't look a team to strike fear into opponents. Former Birmingham and Sunderland man Seb Larsson, now 35, still roams in midfield, while at the back Manchester United's Victor Lindelof will look to guide the back four.
The Swede have always been well organised but they'll need more than that if they are to go far in this tournament.
In Russia, the Swedes helped knock out Germany in the groups before progressing to the last eight. He was subsequently named Sweden's sports coach of the year.
Prior to his role with the national team, Andersson spent his playing and managerial career in his homeland, winning the Allsvenskan title as boss of IFK Norrkoping.
Odds - Title: 80/1; To win group: 7/1; To qualify: 8/15
Best European Championship performance: Quarter-finals (2016)
How they qualified
First, Group G - P10 W8 D1 L1 F18 A5 Pts25
Seven clean sheets were the foundation of Poland's successful qualifying campaign. However, only 18 goals were scored - they were the only group winners to average under two goals per game.
Their low-scoring games continued in this season's Nations League with just six scored and the same number conceded as they finished third in a group containing Italy, Netherlands and Bosnia. They lost twice to the Dutch and once to the Italians, their only wins coming against relegated Bosnia.
Defeat in England and a draw in Hungary has meant a slow start to their World Cup qualifying campaign.
Much focus will be on providing star striker, Robert Lewandowski, with chances.
He's just finished as the top-scorer in Europe's best leagues, scoring a record-breaking 41 in the Bundesliga for Bayern Munich.
He also bagged six in qualifying for this tournament but despite his presence, Poland were far from high-scoring.
Napoli's Piotr Zielinski will look to carve out chances in a midfield where experienced anchor Grzegorz Krychowiak retains a strong presence.
Another veteran, Kamil Glik, will line up alongside Southampton's Jan Bednarek as key components of what is set to be a three-man defence.
The Poles also have good options in goal with Wojciech Szczesny usually keeping out West Ham's Lukasz Fabianski.
Paulo Sousa - Replaced Jerzy Brzeczek, who led Poland to the Finals but in a style which wasn't enough for Polish legend Zbigniew Boniek, now president of the Polish federation.
The Portuguese took charge of his first game in March, immediately changing the team's formation by playing three at the back. He has enjoyed a much-travelled career as a manager, including in the UK with Swansea, QPR and Leicester.
Odds - Title: 500/1; To win group: 25/1; To qualify: 2/1
Best European Championship performance: Last 16 (2016). Also, as part of Czechoslovakia: Winners (1976)
How they qualified
Via play-offs (Third, Group H - P8 W4 D1 L3 F13 A11 Pts13)
Taking just one point off Wales in their qualifying group proved pivotal to them finishing outside the top two in what was a competitive pool.
That left them reliant on the play-offs as a route to the Finals - and they were fortunate for the format of those given they actually only won one game in the 2018/19 Nations League which decided the nations involved.
Again struggled for goals in this season's Nations League campaign, scoring only five as they finished bottom of a group which didn't look the toughest - Czech Republic, Scotland and Israel being their rivals.
Had an up-and-down start to World Cup qualifying, being held by both Cyprus and Malta before upsetting the more-fancied Russia.
There aren't too many stars on the Slovakia roster but a bona fide one is Milan Skriniar, who has played a key role in Inter Milan's Serie A title success this season.
The defender is viewed as the long-term successor to Martin Skrtel, who has now retired from international soccer. Like Skrtel, he pops up with the odd goal, too - three in Serie A this season.
In midfield, the experienced Marek Hamsik and Juraj Kucka both remain from the 2010 World Cup squad. Hamsik, he of the mohawk haircut, is now playing for Gothenburg in Sweden after spending many years at Napoli. The tough-tackling Kucka is set to captain the side.
Newcastle's Martin Dubravka - axed for internal disciplinary reasons in 2018 - looks set to start in goal.
Stefan Tarkovic - Was only appointed between the semi-final and final of the play-offs with the Slovak FA unimpressed by results in the Nations League.
He had previously worked in the national set-up, assisting Jan Kozak, the boss who led Slovakia to Euro 2016.
Is now in the post on a permanent basis.
Spain are another team with home advantage throughout the group stage and given the quality of opposition in this group, it's hard to see them faltering.
They've not been that impressive of late though, while the decision to leave out Sergio Ramos and bring an uncapped Aymeric Laporte straight into the team certainly has potential for disruption among the squad.
They are heavily odds-on to win the group but don't look much of a bet.
Poland and Sweden will both hope to do enough to progress to the last 16 but both are odds-on to achieve that so preference is to focus on the other end of the group.
Slovakia look one of the weakest teams in the competition and it's no doubt they were fortunate to qualify.
One win on penalties in the play-offs and another in extra time got them in but they don't look to have enough and seem unlikely to qualify for the knockout stage.
They are odds-on to finish bottom but perhaps a better way to get with them is to back them to lose every group game at 10/3.
At least one team has finished with no points in every European Championship since its expansion to 16 teams in 1996. We're now at 24 and while that has arguably diluted the quality (and potentially made it easier to collect points), Slovakia look a little out of their depth.
* Odds correct at time of publication