Signs marking the entrance to the Pine Ridge Indian Reservation in South Dakota make it clear when you're literally "off the reservation," but the figurative meaning of the phrase has shifted over time. Kristi Eaton/AP hide caption

itoggle caption Kristi Eaton/AP

Over the past century and a half, visitors have traveled through Yosemite on foot, by carriage, by tram and by car. Now some regions will be once again be accessible only by foot, to protect delicate regions of the park. Courtesy Yosemite National Park Research Library/KQED hide caption

itoggle caption Courtesy Yosemite National Park Research Library/KQED

Nineteen-year-old Bosnian Serb Gavrilo Princip fired the shots that killed the heir to the Austro-Hungarian empire, Archduke Franz Ferdinand, and his wife, Sophie, during a visit to Sarajevo on June 28, 1914. Depending on whom you ask, he's either a hero or a terrorist. Historical Archives Sarajevo/AP hide caption

itoggle caption Historical Archives Sarajevo/AP

Patrick Haggerty dresses in drag in 1959. As a teen, Haggerty learned from his father never to "sneak" around his identity. Courtesy of Patrick Haggerty hide caption

itoggle caption Courtesy of Patrick Haggerty

Mississippi Freedom Democratic Party delegates and supporters stage a demonstration on the boardwalk in front of the Atlantic City Convention Center in 1964. Courtesy of George Ballis/Take Stock hide caption

itoggle caption Courtesy of George Ballis/Take Stock

Aaron Carapella, a self-taught mapmaker in Warner, Okla., has designed a map of Native American tribes showing their locations before first contact with Europeans. Hansi Lo Wang/NPR hide caption

itoggle caption Hansi Lo Wang/NPR

Fannie Lou Hamer was an activist who spoke out for black rights during Freedom Summer. Courtesy of Ken Thompson/General Board of Global Ministries of The United Methodist Church hide caption

itoggle caption Courtesy of Ken Thompson/General Board of Global Ministries of The United Methodist Church

A missing persons poster displays the photographs of civil rights workers Andrew Goodman, James Earl Chaney and Michael Henry Schwerner after they disappeared in Mississippi in June 1964. It was later discovered that they were murdered by the Ku Klux Klan. Bettmann/Corbis hide caption

itoggle caption Bettmann/Corbis

Huguette Clark in 1930. She had a mansion in Connecticut that was never occupied, and her New York apartments were kept up, unoccupied, for more than 20 years. AP hide caption

itoggle caption AP