that governments have been active in covering up alien visitations, like the events at Roswell and the things hidden at Area 51
that Diana Spencer and Dodi Al Fayed were murdered by the intelligence services under command from the British Royal Family, and that the car accident was in fact an intentional killing or cover-up
RFID and other technological innovations are secretly part of a plan to track and control people
the United Nations is a secret socialist plot to destroy American freedom
that the U.S. Government (or, indeed, the New World Order) is behind false flag operations - operations conducted covertly to give the appearance of being conducted by some other group. The World Trade Center attacks in both 1993 and 2001 have been blamed by conspiracy theorists on the FBI and the Bush administration respectively. The train bombings in Madrid and London in 2004 and 2005 have been blamed on a variety of groups other than Islamic terrorists including the government, intelligence services operatives and, in the case of Madrid, ETA, the Basque separatist group. Even Pearl Harbor, it has been suggested, was allowed to happen by shadowy government forces as a way to get the United States to enter World War II. Many link the World Trade Center attacks in 2001 to Operation Northwoods, a declassified plan by the Joint Chiefs of Staff from 1962 to fake an attack on an American airliner by the Cubans to give a pretext to toppling Fidel Castro.
the control of the entire world by a New World Order, a "shadow government". Many believe that the creation of the U.S. Federal Reserve Bank is due to the New World Order.
some public health interventions have been seen as attempts at a conspiratorial form of lifestyle regulation or even mind control - including fluoridation of drinking water supplies, vaccination of infants and responses to widespread transmission of HIV
governments and the medical profession are often implicated in alleged conspiracy theories for creating, or suppressing cures for, diseases like cancer and AIDS.[1]
that governments, pharmaceutical companies and the medical profession are engaged in a conspiracy to suppress alternative and natural medicines because they are effective and provide competition to mainstream medicine, rather than because they are often unproven or dangerous - see, for instance, the title of Kevin Trudeau's book Natural Cures "They" Don't Want You to Know About.
the Protocols of the Elders of Zion, an anti-Semitic forgery produced by the Okhrana, and similar anti-Semitic texts have alleged that the Jews are secretly in control of the whole world.
that the Catholic Church secretly controls world affairs[2]
that the Vatican keeps secret records of the names and locations of Protestants[2]
that the United States is planning to secretly join and construct a single-state North American Union with Mexico and Canada and to impose a Euro-like single currency, the Amero.
the idea that John F. Kennedy was killed by a shadowy cabal or a second gunman on "the grassy knoll" rather than by Lee Harvey Oswald
some claim that U.S. President Bill Clinton's Deputy White House Counsel, Vince Foster was killed by Clinton (as opposed to committing suicide), along with other of Clinton's opponents and those who got in the way of Clinton's career
that the United States government is secretly controlled by Secular Humanists, Jews or any number other groups
that U.S. President Barack Obama is, in a conspiracy with others, hiding his true (Islamic) religious beliefs
that U.S. President Barack Obama is secretly not a "natural born" U.S. citizen, but in fact a British subject or a citizen of Kenya, and will not release his true birth certificate - see Birther Movement
that the High-frequency Active Auroral Research Program (HAARP) in Anchorage, Alaska is a secret weapon or weather control device