*Various theories regarding President [[John F. Kennedy]]'s assassination. There are a number of theories proposed here, generally along the lines that the assassination was not conducted by [[Lee Harvey Oswald]] acting alone, but was part of some larger murder conspiracy. This may be the first of the modern conspiracy theories.
*[[Apollo conspiracy theory]]: The theory that the [[Apollo 11]] lunar landing on July 20, 1969, and indeed the entire Apollo program, was fake. Supporters analyze photographs, and often claim that satellite photographs of [[Area 51]] resemble a movie studio.
*Various [[9/11 conspiracy theories]]. People who embrace these are called [[Truther]]s. The theories generally state that the World Trade Center buildings were not brought down by airplane collisions, but (typically) by detonation of explosives planted earlier. <ref>They claim that Jewish workers had been telephoned in advance and told not to come to work (false), that airplane collisions would have caused the buildings to topple over rather than collapse directly downward (false, ignorant of high-school physics), or that the heat of burning aviation fuel would not raise the temperature sufficiently to melt the girders (false, the temperature to make iron visibly bend is much higher than the temperature to make it lose the strength needed to hold up a building). </ref> Truthers often ascribe the motivation for this to some kind of nefarious scheme by the [[George W. Bush]] administration. Among the web sites promoting these theories are [[Infowars]] and [https://wearechange.org We Are Change].
*The belief that President [[Franklin D. Roosevelt]] knew about the [[Attack on Pearl Harbor]] in advance, and allowed it to happen, so America could get into the war; that officers ignored evidence that the attack had started.<ref>From decrypts of Japanese communications, American intelligence expected a major military operation within that time frame, but believed it would take place in southern Asia.</ref>
*The notion that [[Jews]] are [[Anti-Semitism|conspiring to destroy civilization]]. This one is particularly serious. It has been going on in [[Europe]] for hundreds of years. It led to [[Anti-Semitism]], and, more tragically, the [[Holocaust]] of the [[Nazi Party|Nazi]]s in 20<sup>th</sup> century Germany.<ref>[http://newint.org/features/2004/10/01/conspiracism/ "ZOG Ate My Brains"]</ref>