As early humans spread out across the world, their toughest challenge was colonizing the Americas - because a huge ice sheet blocked the route. It has long been thought that the pioneers, known as Clovis people, arrived about 13,000 years ago, but an underwater discovery in Mexico suggests people arrived earlier than previously thought - and by boat, not on foot. How closely related were these First Americans to today's Native Americans? It's a controversial matter, focused on Kennewick Man. Few other skeletons engender such strong feelings.

Originally released by Public Broadcasting Service (U.S.), 2015. Streaming video file encoded with permission for digital streaming by Infobase on February 13, 2017.

Eva: The First American --(2:39) -- Ice Age: Yucatan Peninsula -- (2:07) -- Ritual Burial in North America -- (3:17) -- Southern Route to North America -- (3:11) -- Clovis People -- (4:14) -- Early Hunters in North America -- (3:44) -- Sporormiella -- (2:22) -- Centuries Before Clovis People -- (2:25) -- Coastal Route -- (3:06) -- Kennewick Man: Early Coastal Migrant -- (2:58) -- Reburial Ceremony -- (1:33) -- Definitive Examination Summary -- (2:58) -- Isotope Signal Revelation -- (3:15) -- No Link to Modern Native Americans -- (3:40) -- Ancient Genomics -- (3:57) -- Results for the Ancient One -- (3:06) -- Explorer Genes -- (3:33) -- Credits: First Peoples: Americas -- (0:36).