(Jon of the Clue Crew shows a map on a screen) During the Pleistocene Epoch, the ocean receded, and Beringia emerged, an example of this 2-word type of isthmus, allowing humans to come from Asia to America,
The 
distance across the Bering Strait from Siberia to Alaska's Seward Peninsula is 
approximately 55 miles, and for several periods during the Pleistocene Ice Ages 
the ... clues in this great detective story regarding human presence in the 
Americas.