An asteroid came close to hitting Earth sometime in 2002. How much damage might it have done?

Asteroid 2002 EM7, a rock 230 feet (70 meters long), is estimated to have the capability of releasing the energy equivalent of a 4 megaton nuclear bomb.

Built in England between 2500 and 1700B.C.E., Stonehenge is one of the earliest observatories or observatory-temples. It is widely believed that its primary function was to observe the mid-summer and mid-winter solstices.