Russian Foreign Minister Sergei Lavrov is on a three-day visit to North Korea, which has provided troops and arms for Russia's war with Ukraine

The Wonsan Kalma resort was opened in a grand ceremony last month by North Korea's leader, Kim Jong Un, who hailed it as a "world-class tourist and cultural destination". The details of how this resort was built have been shrouded in secrecy in a country largely closed to the outside world.