Interesting subject, and one that pre-dates religion and science, the term 'ley line' is quite a modern one (1920's I think) but refers to tracks across the world that join up sites of significant importance, many of which as I said pre-date modern man, neolithic times possibly, why even in the deep distant past that animals and then humans selected sites of importance and then followed them by lines, it is history now, but science has also been trying to explain with ideas such as geo magnetic faults and electrical discharges.
It ties in with history to try and explain sites such as Stone henge or the Glastonbury Tor as two examples, and is still an enigma to this day as to why such sites were chosen, but one such theory has been some sort of connecting line, this 'ley line'
To answer the original question, yes I have known about them a long time.