From sailing ships to spaceships, the development of America is filled with stories of courageous adventurers. Your students will thrill to the exploits of Columbus, Daniel Boone, Lewis and Clark, and John Muir---and the vast country they discovered. Includes onscreen captions; printable teacher's guide, quizzes, and historic documents; and conversations with two explorers of the final frontier. Approx. 50 minutes.