From the earliest times, men and women explored their world. Some searched for trade routes, lost treasures, or new lands to colonize; others traveled as missionaries, to spread religious beliefs. More than anything else, however, what motivated the greatest explorers was simple curiosity:
What was on the other side of that mountain? How wide was North America? Where was the source of the Nile River? In the days before railroads, motor cars, and airplanes, finding out often involved traveling incredible distances overland: on foot, horse, or camel, by wagon or canoe,
and for months, even years, at a time. And it usually meant facing severe dangers, extraordinary hardships, and the uncertainty of not knowing when, if ever, you might make it back home.