More from The National:
Saturday's best photos: from a Russian spacecraft to the Singapore Grand Prix
Friday's best photos: From an astronaut saying goodbye to a Mont Saint-Michel light show
Thursday's best photos: from Italian ice cream to sitting volleyball
Wednesday's best photos: from camel traffic to Bavarian herdsmen - in pictures
Tuesday's best photos: From a land art painting to Pancha Dan festival
Monday's best photos: from the LA Chargers punting to a Turkey cave rescue
Who's who in Yemen conflict
Houthis: Iran-backed rebels who occupy Sanaa and run unrecognised government
Yemeni government: Exiled government in Aden led by eight-member Presidential Leadership Council
Southern Transitional Council: Faction in Yemeni government that seeks autonomy for the south
Habrish 'rebels': Tribal-backed forces feuding with STC over control of oil in government territory
Uefa Nations League: How it Works
The Uefa Nations League, introduced last year, has reached its final stage, to be played over five days in northern Portugal. The format of its closing tournament is compact, spread over two semi-finals, with the first, Portugal versus Switzerland in Porto on Wednesday evening, and the second, England against the Netherlands, in Guimaraes, on Thursday.
The winners of each semi will then meet at Porto’s Dragao stadium on Sunday, with the losing semi-finalists contesting a third-place play-off in Guimaraes earlier that day.
Qualifying for the final stage was via League A of the inaugural Nations League, in which the top 12 European countries according to Uefa's co-efficient seeding system were divided into four groups, the teams playing each other twice between September and November. Portugal, who finished above Italy and Poland, successfully bid to host the finals.