Four two legged play off matches resulted in Switzerland, Croatia, Denmark, and Sweden qualify for next years tournament in Russia.
Croatia dominated their home leg 4-1 against Greece and played out a boreish 0-0 in the second leg to secure qualification.
A Ricardo Rodriguez away goal in the first leg completed Switzerland's road to the World Cup beating Northern Ireland 1-0 on aggregate.
After a tight 0-0 draw in Copenhagen, Denmark and a Christian Eriksen hattrick comfortably saw off Republic of Ireland to take them to the finals.
AEK Athens midfielder Jakob Jahansson got the only goal over two legs for Sweden which saw them beat Italy, who fail to qualify for the first time since 1958.