An olive-green North Korean train, emblazoned with a gold stripe, carried leader Kim Jong Un into China on Tuesday for a grand military parade that President Xi Jinping and Russia's Vladimir Putin will also attend.
Since taking power in 2011, Kim has now made nine international trips and crossed the border into South Korea twice, using his bespoke, bulletproof train for most of his travel.
AFP takes a look at what we know about Kim's preferred mode of transport:
A love of locomotives runs in Kim's family.
His father and predecessor, Kim Jong Il, was known to fear flying, limiting his foreign trips to overland journeys to China and Russia by armored train.
In 2001, the elder Kim rode his train from the North Korean capital Pyongyang to Moscow, a marathon 20,000-kilometer (12,400-mile) round trip that took about 24 days.
The train was well stocked, however, with fresh lobster and drinks, according to an account by a Russian official on board.
According to the official North Korean account, Kim Jong Il was on a train for a "field guidance" visit in 2011 when he died of a heart attack.
The carriages used by Kim Jong Il and his father, North Korea's founder Kim Il Sung, are now on display in Pyongyang.
Unlike his father, Kim Jong Un is not afraid of flying -- he has taken several trips by air, including to China and Singapore, and was once depicted by state media at the controls of an aircraft.
But for his latest trip to Beijing, he again chose the train.
Pyongyang's Korean Central News Agency published photos on Tuesday of a beaming Kim sitting inside a carriage, apparently en route to Beijing.
The North Korean leader was pictured sitting at a wooden desk on which was a laptop, ashtray, printer, lamp and several telephones, in a space furnished with the national flag and what looked like blue velvet curtains.
Foreign Minister Choe Son Hui was seated beside him, with documents laid out in front of her.
Another image showed Kim standing outside the train smoking a cigarette, with Choe and other officials gathered around him.
The train passing through the countryside "makes for a powerful display to the people -- a symbolic image of the leader working long hours on board, even late at night", Park Min-ju, a professor at the National Institute for Unification Education, told AFP.
"It serves both practical and political purposes."
Kim travelled by train for nine nights and 10 days in September 2023 to meet Putin in Russia's far east.
He also rode the train for about 1,200 kilometers to meet Putin in the Russian city of Vladivostok in April 2019.
In February that year, Kim spent around 60 hours on board to Hanoi, Vietnam, for his failed second summit with US President Donald Trump.
Kim has previously visited China four times, travelling by train on his first trip in March 2018 and again in January 2019.
He flew on his private jet, the Chammae-1, for the other two trips in May and June 2018.
But he has not publicly used that plane since 2018, and analysts question its reliability due to its age and maintenance issues.
The Kims reportedly have several near-identical special trains made by a factory in Pyongyang.
Kim's current edition has bulletproof windows, as well as reinforced walls and floors to protect against explosives, according to analysts.
"It is said to be able to withstand most artillery shells -- really essentially a fortress," Lim Eul-chul, a professor at the Institute for Far Eastern Studies at South Korea's Kyungnam University, told AFP.
"I believe it is equipped with the defensive and offensive capabilities to endure virtually any military battle."
Despite being slower than aircraft, experts say the train offers key advantages including greater flexibility in situations such as unexpected attacks.
"A train also allows him to bring along many aides, as well as even vehicles, and unlike an aircraft that could be shot down, a moving train is far harder to target," said Park, the other professor.
Choosing the train over a plane is also a calculated strategy.
"Travelling by train takes a long time, but it also captures global attention," Koh Yu-hwan, emeritus professor of North Korean studies at the South's Dongguk University, told AFP.
"Ahead of major diplomatic events, the world closely tracks his movements, and the prolonged journey helps keep the spotlight on him," Koh said.
Kim was also seen using his armored train domestically when he visited flood-hit areas in North Pyongan Province last summer.
Images released by state media showed Kim about to deliver a speech to residents from a carriage with its doors fully opened, turning it into a makeshift stage.
