April Fools' Day or April Fool's Day (rarely called All Fools' Day[1]) is an annual custom in many Western countries on the 1st of April consisting of practical jokes, hoaxes, and pranks. Jokesters often expose their actions by shouting "April Fool[s]!" at the recipient. Mass media can be involved with these pranks, which may be revealed as such the following day. The custom of setting aside a day for playing harmless pranks upon one's neighbor has been relatively common in the world historically.[2]

A placebo (/pləˈsiːboʊ/ pluh-SEE-boh) is a medicine or treatment intended to appear genuine to its recipient, but which has no pharmaceutical effect.[1][2] Common placebos include inert tablets (like sugar pills), inert injections (like saline), sham surgery,[3] and other procedures.[4]

Guy Fawkes (/fɔːks/; 13 April 1570 – 31 January 1606),[a] also known as Guido Fawkes while fighting for the Spanish, was a member of a group of provincial English Catholics involved in the failed Gunpowder Plot of 1605. He was born and educated in York; his father died when Fawkes was eight years old, after which his mother married a recusant Catholic.

Fawkes converted to Catholicism and left for mainland Europe, where he fought for Catholic Spain in the Eighty Years' War against Protestant Dutch reformers in the Low Countries. He travelled to Spain to seek support for a Catholic rebellion in England without success. He later met Thomas Wintour, with whom he returned to England. Wintour introduced him to Robert Catesby, who planned to assassinate King James I and restore a Catholic monarch to the throne. The plotters leased an undercroft beneath the House of Lords; Fawkes was placed in charge of the gunpowder that they stockpiled there. The authorities were prompted by an anonymous letter to search Westminster Palace during the early hours of 5 November, and they found Fawkes guarding the explosives. He was questioned and tortured over the next few days and confessed to wanting to blow up the House of Lords.