The final four places at the World Cup finals from Europe will be decided via four playoffs.
Who has qualified for the playoffs?
Eight nations are into the playoffs, ranked based on the October 2017 FIFA Ranking.
Seeded: Switzerland, Italy, Croatia, Denmark
Unseeded: Northern Ireland, Sweden, Republic of Ireland, Greece
Who can play each other?
Switzerland, Italy, Croatia and Denmark will be the top-ranked teams, and thus seeded. They were also the four runners-up who had the best record in group qualifying.
Each seeded nation will be drawn to play an unseeded nation. That means, for instance, Northern Ireland and Republic of Ireland cannot play each other in the playoffs.
Are the seeded teams automatically at home in the second leg?
No, FIFA will also draw which nation is at home in the first leg for each of the four ties.
When is the draw?
It takes place at 2 p.m. CET (1 p.m. BST) on Tuesday, Oct. 17.
When will the matches be played?
The first legs will be Nov. 9 to 11, and the second legs Nov. 12 to 14.
Do away goals count?
Yes, and if teams are still level after the two legs the game will go to a penalty shootout.