Such intrepid 19th-century explorers as Joe Walker, John Wesley Powell, Benjamin Bonneville, Jedediah Smith and others explored much of the West, yet there remain corners for curious minds to explore.
The MacMillan Arctic Expedition marked the first productive use of aircraft in Arctic exploration by Americans and brought Richard Byrd into the national limelight.
In the closing days of the 17th century, honest, peace-loving folk in both England and its North American colonies feared, above all, the French, divine judgment, and William Kidd.
The only woman on the 1811-12 overland expedition led by Wilson Price Hunt, Marie Dorion endured more hardships than a more famous female Indian traveler, Sacagawea.
Tales of the adventures that befell three conquistadores and their Moorish slave during the sixteenth century led to Spain's Francisco Vásquez de Coronado's exploration of what is now the American Southwest.
Over the vast, frozen wastes of the Artic is the last place anyone would want his airplane to quit.
Three generations of British mountaineers committed themselves to standing where no one ever had before.
It took 30 years to learn the fate of the first expedition to fly across the North Pole.
The Fokker Trimotor Josephine Ford survived mishaps and beat fierce competition to be the first aircraft to fly over the top of the world, carrying Richard E. Byrd into history.
In 1869, John Wesley Powell defied the myth of the Colorado River's invincibility and led the first expedition to navigate through the Grand Canyon.
Details of her life remain sketchy, and the time and place of her death are still debated, but the young Indian woman who assisted Meriwether Lewis and William Clark on their great journey west has a secure place in history.
Long March of Lewis and Clark
Its mission over, the Corps of Discovery disbanded and its members sought their own destinies. Some of them passed from the historical record, but others had adventures that made their experiences with Lewis and Clark seem almost tame by comparison.
For 200 years, William Bligh has been known as the tyrant of the Bounty, but he was probably not the villain legend depicts, and the famous mutiny was just one of the many dramatic events in his stormy life.