Looking at the extent of stone circles in Wales, the growth of Celtic hill forts and what they reveal about the changing society of that time.

Volcanic eruptions and cold summers leave lasting marks in the wood of northern trees, unlocking the secrets of past climate extremes.

including 12 crest stones for playoff teams and one diamond in the center for the national championship, according to ESPN. One side of the ring displays the Atlanta skyline in honor of the title ...