Which of the following nations was NOT a belligerent in World War I?

The story behind the answer

Denmark is correct: it maintained strict neutrality throughout World War I, guarding its coasts and the Danish Straits but avoiding combat to navigate between nearby Germany and the British blockade. By contrast, Romania joined the Allies in 1916 seeking Transylvania; Greece entered in 1917 after the National Schism resolved in favor of Venizelos and the Allies; and Portugal joined in 1916 and sent troops to the Western Front.

Memory tip: In WWI most Scandinavian countries—Denmark, Norway, and Sweden—along with the Netherlands, Spain, and Switzerland stayed neutral, while states on Europe’s fringes like Portugal, Romania, and Greece were eventually pulled into the war. Think “Scandi stayed still” to remember Denmark’s neutrality.