In 1620, exactly 400 years ago, the Mayflower left its dock in London for a journey to the opposite edge of the Atlantic. The 102 passengers on board were pioneers, the first handful of English colonizers to reach the New World. The boat left them in Plymouth, Massachusetts, and today 30 million Americans claim a connection with that original group. One hundred museums, libraries, and archives across the U.K., the U.S., and the Netherlands have advised on the exhibition ”Mayflower 400: Legend & Legacy,” which examines the culture and conflicts brought over four centuries ago. Representing the civilization already rooted in America, a collection of Native American art traces back 12,000 years and gives voice to those truly first in the New World. —E.C.