"Get that guy!" Soldiers shouted as Travis King ran laughing over the border into North KoreaA country formed in 1945 when Japanese-occupied Korea was split between a Communist government in the north and a capitalist one in the south. Today it is extremely reclusive, and hostile to the West..

The US soldier was supposed to be flying home. But instead he has disappeared, "absent without leave", into Kim Jong-unThe leader of North Korea since 2011. 's prison state.

Since the pandemic, this secretive country has become even more isolated. Its borders are shut. No one is allowed out. The US bans its citizens from travelling there due to the risk of being sent to prison.

In 2016, the country jailed student Otto Warmbier for stealing a hotel poster. Sweden helped negotiate his release because the US has no embassyThe workplace of a group of government officials who represent their country in another country. in North Korea, but he died not long after returning.

Tension is rising. This month, North Korea tested "its most powerful" missile yet, capable of reaching the US.

In the 1950s, the US backed South Korea in a war against the North. No peace treaty was signed, and the countries are technically still at war. Last month, a rallyA big meeting of people to support a cause. in PyongyangThe capital of North Korea. In the early 20th Century it was a centre of Christianity known as the "Jerusalem of the East". called for a "war of revenge" to destroy America.

The fear is this could go nuclear. The day King crossed the border, a US nuclear-armed submarine arrived in South Korea. Kim Jong-un has vowed to build more nukes. Expert Ankit Panda fears he is preparing for war.

North Korea has "not yet answered" the US Army's call and may be in no rush to send King back. But could this really start World War Three?

Countries have fought over less. In 1859 an American farmer caused an international incident when he shot a British-owned pig on a disputed island near VancouverA city on the west coast of Canada which is consistently named as one of the best places in the world to live.. In 1925, a stray dog on the Greece-Bulgaria border led to a misunderstanding that left 50 dead.

These odd events often follow years of tension. But expert Leif-Eric Easley doubts Pyongyang have much to gain by holding on to King. In a "best-case scenario," he says it might encourage the two sides to start talking again.

Yes: There is a real risk that events will spiral out of control. With little dialogue between the two sides, small accidents can turn into major misunderstandings. The consequences could be catastrophic.

No: Kim Jong-un is bluffing. War would destroy his regime. His missile tests are designed to strengthen his hand in future talks. So he will use King's capture to his advantage but not to start a war.

Or... The scary truth is we just do not know. An incident like this should not cause war, but history shows that it can. We know very little about what is going on inside North Korea and what they will do next.