We start with two men who were among the country’s most skilled explorers, personally hand-picked by Thomas Jefferson, to add an expansive new chapter to the story of the United States.

With them was a pregnant 16-year-old (but she could have been younger), accompanying a man who had purchased her to become his “wife” a few years earlier.

Ahead of them lay 5,000 miles of the unknown country. That was in 1804. The men were Lewis and Clark. The girl was Sacagawea, who is thought to have died on this week, December 20, 1812.