Ground-penetrating radar has been used to determine the size of one of the Avebury megaliths. Avebury, in Wiltshire, England, is home to a megalithic site larger and older than nearby Stonehenge. Now, one of the largest of the megalithics has been discovered and is being analyzed with radar to determine its actual size which could be up to 100 tons. The stone, along with that of its neighbor, has been fenced off from tourists for fear that the stone might fall. The desire for safety has led to the current measurements by National Trust and English Heritage archaeologists.