HBO has ordered a six-hour miniseries about American explorers Meriwether Lewis and William Clark, the network announced Friday.

Lewis and Clark is being produced by Tom Hanks, Edward Norton, Brad Pitt, Dede Gardner, Tim Kelly and Adam Leipzig. The miniseries is based on the book Undaunted Courage by Stephen A. Ambrose.

“In Lewis and Clark, we can see American idealism and the breathtaking natural beauty of the continent, as well as the complexities and tragedies of what came to be known as America’s ‘manifest destiny,’” said HBO programming president Michael Lombardo. “We are tremendously excited to bring together this incredible group of talents to tell a seminal American story.”

HBO and National Geographic Studios are producing with Playtone, Plan B and Class 5. Norton, Michelle Ashford and John Curran are writing with Curran slated to direct. Casey Affleck will play Lewis and Matthias Schoenaerts will play Clark. [source]