Large ancient stones such as found in Stonehenge, most are found on ley lines and emit powerful magnetic fields.
The large standing stones of the British Isles which were probably erected as astronomical observation points or holy sites. Stonehenge on England's Salisbury Plain is probably the most well known.
Literally, "great stone"; a large, toughly hewn stone used in the construction of monumental prehistoric structures. megalithic (adj.). See also cromlech, dolmen, menhir.