There are as you will know many professional dowsers who make their living finding underground water, and other things. It's something I can do. For example some friends asked my to dowse the locations of some underground pipes so they would have to dig up lots of their concrete farmyard to find them. I marked the location with a bit of yellow road crayon - and guess what - the pipes were exactly where I said they would be - much to the surprise of the digger driver. If you dowse a straight alignment of ancient sites you can follow the line to find - guess what - ancient sites! I've seen dowsing work very well. I've also seen people mooning about the place with ruddy great crystal pendants finding all sorts of non-existent new-age crap. Like many things in life it depends on how much effort you are prepared to put into learning a skill.