I remember reading this book in college many years ago, when my teenager started coming in with all these school yard theories and strange facts I had to order this book and give it to him to read. I remember being taking with the Nasca Plain, the Pyramids etc. now that NatGeo has researched and explained these things I guess some of the mystery has gone out of it. Anyway if your teen comes home with all sorts of theories let them know it is nothing new and people have been trying to explain things for a long time. The Mayan calender anyone? I just wonder what explainations people will have for things like Mt Rushmore or whatever in the future. Anyway the book is still a fun read even if it is a bit dated.