1.

People who think that the Apollo moon landings were not all that they seemed at the time believe that Nasa faked some or all of the landings. Some of the theories surrounding this subject are that the Apollo astronauts did not land on the Moon; Nasa and possibly others intentionally deceived the public into believing the landings did occur by manufacturing, destroying, or tampering with evidence, including photos, telemetry tapes, transmissions, and rock samples; and that Nasa and possibly others continue to actively participate in the conspiracy to this day.

Those who think that Nasa faked some or all of the landings base their theories on photographs from the lunar surface which they claim show camera crosshairs partially behind rocks, a flag planted by Buzz Aldrin moving in a strange way, the lack of stars over the lunar landscape and shadows falling in different direction. Many commentators have published detailed rebuttals to the hoax claims, and these theories have been generally discounted but belief in them - particularly on the web - persists.

2.

A conspiracy in which powerful and secretive groups (the Illuminati, the Bilderberg Group and other shadowy cabals) are plotting to rule mankind with a single world government. Many historical events are said to have been engineered by these groups with one goal - the New World Order (NWO). The groups use political finance, social engineering, mind control, and fear-based propaganda to achieve their aims. Signs of the NWO are said to be the pyramid on the reverse of the Great Seal of the United States, inset, strange and disturbing murals at Denver International Airport, pictured, and pentagrams in city plans. International organisations such as the World Bank, the IMF, the European Union, the United Nations, and Nato are listed as founding organisations of the New World Order.

3.

Theorists believe that President Franklin Roosevelt provoked the Japanese attack on the US naval base in Hawaii in December 1942, knew about it in advance and covered up his failure to warn his fleet commanders. He apparently needed the attack to provoke Hitler into declaring war on the US because the American public and Congress were overwhelmingly against entering the war in Europe. Theorists believe that the US was warned by the governments of Britain, the Netherlands, Australia, Peru, Korea and the Soviet Union that a surprise attack on Pearl Harbor was coming and that, furthermore, the Americans had intercepted and broken all the important Japanese codes in the run up to the attack.

4.

A popular theory in the Muslim world is that the tsunami could have been caused by an Indian nuclear experiment in which Israeli and American nuclear experts participated. Several newspapers in Egypt and the Middle East alleged that India, in its heated nuclear race with Pakistan, has acquired sophisticated nuclear technology from the US and Israel, both of which "showed readiness to co-operate with India in experiments to exterminate humankind," beginning with the heavily populated Muslim regions of southeast Asia, where the bulk of casualties took place.

5.

Based on the theories of Dr William Campbell Douglass, many believe that that HIV was genetically engineered in 1974 by the World Health Organisation. Dr Douglass believed that it was a cold-blooded attempt to create a killer virus which was then used in a successful experiment in Africa. Others have claimed that it was created by the CIA or the KGB as a means to reduce world population.