Jessica Estepa

USA TODAY

President Trump ordered a missile launch against Syria on Friday, in response to a chemical weapons attack.

And some are wondering (seriously and with memes) whether this is the start of World War III.

Let's take a step back for a moment. World War I began in 1914, following the assassination of Archduke Franz Ferdinand, heir to the Austro-Hungarian Empire. A month-long diplomatic crisis ensued, eventually leading to the empire declaring war on Serbia.

World War II began when Germany invaded Poland in 1939, leading to Britain and France to declare war on Germany days later.

We don't yet know where Trump's single action may lead. House Minority Leader Nancy Pelosi, D-Calif., has called on Speaker Paul Ryan, R-Wis., to convene the House — which has recessed for Easter — to allow members to debate military force against Syria. World leaders have started to take sides, with Syria, Russia and Iran condemning the launch and Saudi Arabia and Israel praising Trump for taking action.