North Korea has claimed to have destroyed the Punggye-ri test site, which had been previously used for numerous nuclear tests.
Officials from Kim Jong Un's regime blew up tunnels at the site in front of some 20 foreign journalists from the US, UK, Russia, China, and South Korea on May 24, 2018.
Tom Cheshire, a Sky News correspondent who was invited to witness the destruction from 500 metres away, described a "huge explosion," seeing part of a hill collapsing, and a wooden observation cabin being blown to "smithereens."
He also described doors to a tunnel being "theatrically rigged," and seeing wires and plastic bags strewn everywhere.
The journalists, who were staying in Wonsan, had to take a 12-hour overnight train and a four-hour bus, and then hike for two hours in order to get to the test site, located in North Korea's sparsely-populated northeast.
Punggye-ri is believed to be where North Korea carried out at least five nuclear tests in the past, including in September 2017, when the regime claimed to have tested a hydrogen bomb.
The destruction of the test site is meant as a show of good will, but it has been done in a particularly authoritarian way, Business Insider's Alex Lockie previously reported.
South Korean journalists had been excluded from the trip until the last minute as the North protested a US-South Korean military drill. The destruction of the tunnels was also done according to North Korea: It does not meet US or international standards for verifiable or complete denuclearisation.
Chinese authorities also said in April 2018, that Punggye-ri had collapsed. In September 2017, analysts also told The Washington Post that the mountain was suffering from "tired mountain syndrome" after its numerous nuclear tests.
Moreover, if North Korea truly has completed its nuclear programme, as it has claimed, it no longer needs an active test site anyway.
Kim is scheduled to meet US President Donald Trump in June 2018, although Trump said the summit could be delayed.
This article originally appeared on Business Insider. Follow @BusinessInsider on Twitter.