Not impressed? It’s only two more life spans to William Shakespeare. Two more beyond that, and the only Europeans to see America are those who sailed from Greenland. You’re ten lifetimes from the occupation of Damietta during the fifth crusade. Twenty from the founding of Great Zimbabwe and the Visigoth sack of Rome. Make it forty, and Theseus, king of Athens, is held captive on Crete by King Minos, the Olmecs are building the first cities in Mexico, and the New Kingdom collapses in Egypt.—Science Friday: Sixty Men from Ur