National Geographic Specials Season 15, Episode 4: The Tigris Expedition: In Search of Our Beginnings

Follows explorer Thor Heyerdahl's crew as they sail their reed boat over routes believed to have been followed by Sumerian traders 5000 years ago. Watch National Geographic Specials Season 15, Episode 4 The Tigris Expedition: In Search of Our Beginnings in HD free online. Enjoy high-quality streaming of National Geographic Specials Season 15, Episode 4 and share your thoughts in the comments below!