traffic in Washington DC, bollards—sturdy, vertical posts—were added to prevent security breaches by automobiles. (11) In 1950, an assassination attempt on President Harry S. Truman further raised concerns over the safety of the President. (12) In the 20th century, there were numerous instances of the White House perimeter being breached by those who wished to reach the President. (13) On April 13, 1912, Michael Winter made it several feet inside the front door of the White House before being stopped by staff. This was his second attempt to reach President William Howard Taft. (14) On September 26, 1963, Doyle Allen Hicks rammed his pickup truck through the White House gates and drove 25 feet into the North Portico main entrance. He intended to reach President John F. Kennedy. (15) On February 17, 1974, Robert K. Preston, an Army private, stole a helicopter from Fort Meade, Maryland. He hovered over the Washington Monument and the White House grounds before leading two State police helicopters on an aerial chase around Maryland and Washington, DC. Preston then returned to the White House and officers were forced to shoot at the helicopter. Preston was upset about flunking out of flight school. (16) On February 22, 1974, Samuel Joseph Byck tried to hijack a Delta passenger jet at Baltimore-Washington International Airport. His intention was to crash the jet into the White House. He forced his way onto the plane and killed an airport policeman and the copilot before being shot by police. (17) On December 25, 1974, Marshall Fields crashed his automobile through the Northwest Gate of the White House and drove close to the North Portico. He threatened to detonate explosives which he had strapped to his body. Fields surrendered to officials after hours of negotiation. (18) In October 1978, Anthony Henry scaled the White House fence while wielding a knife. He slashed two officers before White House guards were able to subdue him. He intended to find President Jimmy Carter. (19) On September 12, 1994, Frank Eugene