Next year's World Cup sees an old rivalry revived as Spain and Portugal meet in the group stage. Defeat for either 2010 World Cup winner Spain or reigning European champion Portugal means they would need to be careful against fellow Group B nations Morocco and Iran to avoid early elimination.
Meanwhile, reigning champion Germany starts its defence against Mexico at Moscow's vast Luzhniki stadium in another centrepiece game.
Here are six World Cup group stage games to watch:
RUSSIA vs. SAUDI ARABIA
June 14, Moscow
It may look more like a friendly than a show-stopping World Cup opener, but the first game of the tournament is always special. Ranked 63rd and 65th in the world respectively, the Saudis and Russians are the worst teams in the tournament according to FIFA. At least they're evenly matched, which could make for an exciting spectacle.
Saudi Arabia won their only previous meeting 4-2 in 1993 friendly.
PORTUGAL vs. SPAIN
June 15, Sochi
For many, this will be the game that really kicks off the World Cup in style — Cristiano Ronaldo against Andres Iniesta, the reigning European champion against the 2010 World Cup winner.
Spain beat Portugal at the 2010 World Cup, and again in the semifinals of the 2012 European Championship, going on to win the tournament both times. Their World Cup meeting on the Black Sea coast may not be a thriller, though — the 2010 games finished 1-0, and the second was a goalless draw decided on penalties.
ICELAND vs. ARGENTINA
June 16, Moscow
The smallest nation ever to qualify for the World Cup has a huge reward. Lionel Messi's Argentina risks becoming the latest victim of the Icelanders, who beat England and drew with Portugal at last year's European Championship, winning the hearts of neutral fans across the continent along the way.
If Argentina drops points, it will be under more pressure to beat tenacious Croatia and Nigeria in its next games.
The stadium in Moscow has a capacity of 45,000 — or more than 10 percent of Iceland's population of around 330,000. If last year is anything to go by, there will be a huge exodus of Icelanders heading to Russia.
GERMANY vs. MEXICO
June 17, Moscow
The title defence begins here for Joachim Loew and Germany. The venue — Moscow's 81,000-capacity Luzhniki — befits a world champion, while Mexico brings quality opponents like forward Javier Hernandez and midfielder Giovani dos Santos.
Anything less than a win will be a disappointment for Germany, which beat Mexico 4-1 in the Confederations Cup semifinals in June. Germany showed its immense strength in depth by winning that tournament with an experimental team lacking some of its biggest stars.
Sweden and South Korea are on hand in Group F to take advantage of any dropped points.
SERBIA vs. SWITZERLAND
June 22, Kaliningrad
Switzerland is a long way from the Balkans, but there could be a Yugoslavian rivalry in Group E. The Swiss have several players of Kosovan and Albanian heritage in their squad, such as midfielders Granit Xhaka and Xherdan Shaqiri, while the coach is Vladimir Petkovic, who comes from a Bosnian Croat background.
That won't escape the attention of the Serbian fans, whose games against other Balkan nations routinely require heavy security because of the region's long-running rivalries between ethnic groups.
With Brazil the heavyweight in Group E, both teams will likely fight for second place, with Costa Rica also in the mix.
ENGLAND vs. BELGIUM
June 28, Kaliningrad
It's almost an English Premier League game when England meets Belgium in their final group stage game.
England coach Gareth Southgate predicts "banter" at various Premier League clubs, thanks to Belgium's Premier League stars like Eden Hazard, Thibaut Courtois and Romelu Lukaku.
Belgium's coach Roberto Martinez is a Premier League fixture too from his time with Everton and Wigan.
If both England and Belgium have won their preceding games against Panama and Tunisia, the meeting could lose its edge — but if either team risks elimination it will be a crucial fixture.
