The bus used by President Obama to travel around Minnesota, Iowa, and Illinois is parked on the tarmac of Minneapolis-St. Paul Airport on Aug. 15. Jason Reed/Reuters
President Obama's limousine, a.k.a. 'The Beast,' is parked as he meets with firefighters and first responders at Engine 54, Ladder 4, Battalion 9 before visiting the National Sept. 11 Memorial at Ground Zero in New York on May 5. Charles Dharapak/AP/File
The sun sets behind Air Force One at Austin Bergstrom International Airport while President Obama visits Austin, Texas on May 10. Stephen M. Keller/AP/File
President Obama walks across the South Lawn of the White House following his return on Marine One helicopter in Washington on Aug. 9. Mr. Obama made an unannounced trip to Dover Air Force Base, Del., to pay tribute to the 30 US troops killed over the weekend in Afghanistan. Pablo Martinez Monsivais/AP
Wellwishers line a Cartagena, Colombia street as the limousine of then-President Bill Clinton passes by on Aug. 30, 2000. Marcelo Salinas/AFP/Getty Images/Newscom/File
President Ronald Reagan's presidential limousine is on display at the Ronald Reagan Presidential Library and Museum in Simi Valley, Calif., in 2005. Joe Sohm/Newscom/File
President Richard Nixon waves from the presidential limousine during his inaugural parade in Washington on Jan. 20, 1969. White House/National Archives/MCT/Newscom/File
In this undated photograph, President John F. Kennedy and his wife Jackie greet a crowd in a stadium while riding in an open limousine. JFK Collection/ZUMA Press/Newscom/File
Dwight D. Eisenhower's 1950 Lincoln 'bubbletop' presidential limousine is on display at The Henry Ford Museum in Dearborn, Mich. DanitaDelimont.com/Newscom/File
Pictured is The Independence, presidential aircraft for President Harry S. Truman, on display in Dayton, Ohio. DanitaDelimont.com/Newscom/File
President Franklin Delano Roosevelt is shown on a train journey through the US in the 1930s. AKG Images/Newscom/File
President William Howard Taft waves farewell to the crowd from the rear of his special train after the opening of the Gunnison Tunnel in Colorado in 1909. AKG Images/Newscom/File
This undated photograph was taken outside the Rockwell House Hotel in Glen Falls, New York. It shows President Ulysses S. Grant wearing a top hat while sitting in his carriage, surrounded by a crowd. Newscom/File
Cornelius Gurlitt, the son of one of Adolph Hitler’s main art dealers, bequeathed the collection to the Kunstmuseum Bern, which has said it will thoroughly research the provenance of each piece of art and promises a transparent process.
A Swiss museum agreed on Monday to accept an art collection hoarded during the Nazi era and left to a German recluse, saying that its approach of broad transparency could set a new standard in the handling of Nazi-looted art.