It's cut itself off from the rest of the world and the trade that North Korea does do with foreign territories has now largely been severed as a result of sanctions. Despite this, the reclusive county's elite still manage to enjoy lives full of luxuries, many of them originating from abroad, and the country's leader Kim Jong-un is able to fund a huge military programme. So where does all this money come from? We uncover the cash flowing into and out of North Korea.