There are over 60 round towers, mainly in Ireland, with a few in Scotland. It used to be about 120 towers. There have been many questions about why they were built, & what they were used for. It’s believed that they were large paramagnetic antennae that channeled healing energy.
The type of stone to use, and the shape of the structure as a healing device, was well known to those who were more in touch with nature. We have lost that connection.
Here is the link to the fascinating articles. It links you to all 4 parts of the article, at the bottom of the site page. http://www.trcb.com/travel/destinations/the-enigma-of-the-irish-round-towers-part-one-5366.htm
Another great article on paramagnetics and ORMUS elements http://www.subtleenergies.com/ormus/tw/paramag.htm