I found Cuzco a very safe place and a city I want to visit again. If you stay around the city center I am sure you will be fine. As for Lima the hotel I stayed in near the airport would not let us out of the mini van until we were inside the gates. I went out onto the balcony and herd loads of screaming and unpleasant sounds. I asked the hotel staff about going for a walk and they said it is not safe enough. Like all cities in the world I am sure there are safe and unsafe places. I picked an unsafe one!