I visited North Korea on a day trip from Seoul back in 2008, when the border was open to limited tours of the city of Kaesong, just north of the DMZ. Security was especially high due to a tourist being shot the previous day at the Keumgang Mountain area in the eastern part of North Korea - the only other place open to tours direct from South Korea by bus at that time. But we made it through and back safe and sound. The contrast from modern-day Seoul just an hour or so away was striking. We saw some of the day-to-day life in the old city, but they didn't let us take photos of people on the streets, unfortunately. We were allowed to walk around freely at the mountainous region where this waterfall is located - about 25 minutes away from Kaesong. The waterfall is called Pakyon Falls, and it is supposedly one of the top 3 most famous waterfalls in the country. One good thing about North Korea is that the nature (at least in some parts) is relatively untouched and appears unpolluted.