CNN's Will Ripley was among a group of journalists who traveled to North Korea to witness the apparent destruction of three nuclear tunnels at Punggye-ri nuclear test site on Thursday.
Ripley told CNN's Anderson Cooper that he traveled more than 15 hours to get to the site.
Once Ripley arrived, they received a briefing from a North Korean official. The journalists got to look inside the nuclear tunnels, which were rigged with explosives. North Korea has used the tunnels to conduct six nuclear tests since 2006, Ripley said.
He said they then hiked up a ravine and watched North Korean officials blow up observation buildings, a metal foundry and living quarters at the nuclear test site.
"It was pretty dramatic images, but it was hard really to know exactly what we were seeing," Ripley said.
North Koreans officials learned that President Trump had canceled the upcoming summit hours after the explosions, he said.
"It was really a surreal moment," Ripley said.