Tourism is allowed, but highly resticted. US travelers to North Korea must get a visa and official permission to enter, and these are only granted after you've booked a guided tour with a state sanctioned agency. Travel is only possible as part of a guided tour. You cannot roam about independently. A 53-year old female South Korean tourist made the mistake of wandering independently into a restricted zone and was shot dead by a North Korean soldier. Those fellas don't mess around. You should also have all your documents in order and with you at all times otherwise you might be accused of having entered illegally and risk long detention and possible imprisonment.