Question: When did the Beatles become popular in the country where helicopters are based in the nation that recently voted to leave an example of a federal union?

full_context: Document 1: Sgt. Pepper's Lonely Hearts Club Band: Sgt. Pepper's Lonely Hearts Club Band is the eighth studio album by English rock band the Beatles. Released on 26 May 1967 in the United Kingdom and 2 June 1967 in the United States, it was an immediate commercial and critical success, spending 27 weeks at the top of the UK albums chart and 15 weeks at number one in the US. On release, the album was lauded by the vast majority of critics for its innovations in music production, songwriting and graphic design, for bridging a cultural divide between popular music and legitimate art, and for providing a musical representation of its generation and the contemporary counterculture. It won four Grammy Awards in 1968, including Album of the Year, the first rock LP to receive this honour.
Document 2: Brexit: Brexit (/ ˈbrɛksɪt, ˈbrɛɡzɪt /) is the impending withdrawal of the United Kingdom (UK) from the European Union (EU). In a referendum on 23 June 2016, 51.9% of the participating UK electorate voted to leave the EU; the turnout was 72.2%. On 29 March 2017, the UK government invoked Article 50 of the Treaty on European Union. The European Union (Withdrawal) Act 2018 declares ``exit day ''to be 29 March 2019 at 11 pm UTC.
Document 3: Army Air Corps (United Kingdom): The Army Air Corps (AAC) is a component of the British Army, first formed in 1942 during the Second World War by grouping the various airborne units of the British Army (which are no longer part of the AAC). Today, there are eight regiments (7 Regular Army and 1 Reserve) of the AAC as well as four Independent Flights and two Independent Squadrons deployed in support of British Army operations across the world. They are located in Britain, Brunei, Canada, and Germany. Some AAC squadrons provide the offensive and air assault elements of 16 Air Assault Brigade through Joint Helicopter Command.
Document 4: Brexit: In a referendum on 23 June 2016, 51.9% of the participating UK electorate voted to leave the EU, out of a turnout of 72.2%. On 29 March 2017, the UK government invoked Article 50 of the Treaty on the European Union. The UK is thus due to leave the EU at midnight on 30 March 2019 Central European Time (11 pm on 29 March 2019 GMT).
Document 5: The Beatles: The Beatles were an English rock band formed in Liverpool in 1960. With members John Lennon, Paul McCartney, George Harrison and Ringo Starr, they became widely regarded as the foremost and most influential act of the rock era. Rooted in skiffle, beat and 1950s rock and roll, the Beatles later experimented with several musical styles, ranging from pop ballads and Indian music to psychedelia and hard rock, often incorporating classical elements and unconventional recording techniques in innovative ways. In 1963 their enormous popularity first emerged as ``Beatlemania ''; as the group's music grew in sophistication, led by primary songwriters Lennon and McCartney, the band were integral to pop music's development into an art form and came to be perceived as an embodiment of the ideals shared by the counterculture of the 1960s.
Document 6: Politics of the United States: The United States is a federal republic in which the president, Congress, and federal courts share powers reserved to the national government according to its Constitution. At the same time, the federal government shares sovereignty with the state governments.
Document 7: Beatlemania: The Beatles' rise to prominence in the United States in February 1964 was a significant development in the history of the band's commercial success. In addition to establishing the Beatles' international stature, it changed attitudes to popular music in the United States, whose own Memphis - driven musical evolution had made it a global trend - setter.
Document 8: Federalism: In contrast, Europe has a greater history of unitary states than North America, thus European "federalism" argues for a weaker central government, relative to a unitary state. The modern American usage of the word is much closer to the European sense. As the power of the Federal government has increased, some people have perceived a much more unitary state than they believe the Founding Fathers intended. Most people politically advocating "federalism" in the United States argue in favor of limiting the powers of the federal government, especially the judiciary (see Federalist Society, New Federalism).
Document 9: Hard rock: Blues rock acts that pioneered the sound included Cream, The Jimi Hendrix Experience, and The Jeff Beck Group. Cream, in songs like "I Feel Free" (1966) combined blues rock with pop and psychedelia, particularly in the riffs and guitar solos of Eric Clapton. Jimi Hendrix produced a form of blues-influenced psychedelic rock, which combined elements of jazz, blues and rock and roll. From 1967 Jeff Beck brought lead guitar to new heights of technical virtuosity and moved blues rock in the direction of heavy rock with his band, The Jeff Beck Group. Dave Davies of The Kinks, Keith Richards of The Rolling Stones, Pete Townshend of The Who, Hendrix, Clapton and Beck all pioneered the use of new guitar effects like phasing, feedback and distortion. The Beatles began producing songs in the new hard rock style beginning with the White Album in 1968 and, with the track "Helter Skelter", attempted to create a greater level of noise than the Who. Stephen Thomas Erlewine of AllMusic has described the "proto-metal roar" of "Helter Skelter," while Ian MacDonald argued that "their attempts at emulating the heavy style were without exception embarrassing."
Document 10: Army Aviation Corps (India): The Army Aviation Corps is a component of the Indian Army, formed on 1 November 1986. The aviation arm is headed by a Director General of the rank of Lt General at the Army HQ, New Delhi.
Document 11: Anti-aircraft warfare: Poland's AA defences were no match for the German attack and the situation was similar in other European countries. Significant AA warfare started with the Battle of Britain in the summer of 1940. 3.7-inch HAA were to provide the backbone of the groundbased AA defences, although initially significant numbers of 3-inch 20-cwt were also used. The Army's Anti-aircraft command, which was under command of the Air Defence UK organisation, grew to 12 AA divisions in 3 AA corps. 40-mm Bofors entered service in increasing numbers. In addition the RAF regiment was formed in 1941 with responsibility for airfield air defence, eventually with Bofors 40mm as their main armament. Fixed AA defences, using HAA and LAA, were established by the Army in key overseas places, notably Malta, Suez Canal and Singapore.
Document 12: Brexit: In a referendum on 23 June 2016, 51.9% of the participating UK electorate voted to leave the EU, out of a turnout of 72.2%. On 29 March 2017, the UK government invoked Article 50 of the Treaty on the European Union. The UK is thus due to leave the EU on 29 March 2019.
Document 13: Anti-aircraft warfare: In Britain and some other armies, the single artillery branch has been responsible for both home and overseas ground-based air defence, although there was divided responsibility with the Royal Navy for air defence of the British Isles in World War I. However, during the Second World War the RAF Regiment was formed to protect airfields everywhere, and this included light air defences. In the later decades of the Cold War this included the United States Air Force's operating bases in UK. However, all ground-based air defence was removed from Royal Air Force (RAF) jurisdiction in 2004. The British Army's Anti-Aircraft Command was disbanded in March 1955, but during the 1960s and 1970s the RAF's Fighter Command operated long-range air -defence missiles to protect key areas in the UK. During World War II the Royal Marines also provided air defence units; formally part of the mobile naval base defence organisation, they were handled as an integral part of the army-commanded ground based air defences.
Document 14: Federalism: Federalism in the United States is the evolving relationship between state governments and the federal government of the United States. American government has evolved from a system of dual federalism to one of associative federalism. In "Federalist No. 46," James Madison asserted that the states and national government "are in fact but different agents and trustees of the people, constituted with different powers." Alexander Hamilton, writing in "Federalist No. 28," suggested that both levels of government would exercise authority to the citizens' benefit: "If their [the peoples'] rights are invaded by either, they can make use of the other as the instrument of redress." (1)
Document 15: Federalism: Until recently, in the absence of prior agreement on a clear and precise definition, the concept was thought to mean (as a shorthand) 'a division of sovereignty between two levels of government'. New research, however, argues that this cannot be correct, as dividing sovereignty - when this concept is properly understood in its core meaning of the final and absolute source of political authority in a political community - is not possible. The descent of the United States into Civil War in the mid-nineteenth century, over disputes about unallocated competences concerning slavery and ultimately the right of secession, showed this. One or other level of government could be sovereign to decide such matters, but not both simultaneously. Therefore, it is now suggested that federalism is more appropriately conceived as 'a division of the powers flowing from sovereignty between two levels of government'. What differentiates the concept from other multi-level political forms is the characteristic of equality of standing between the two levels of government established. This clarified definition opens the way to identifying two distinct federal forms, where before only one was known, based upon whether sovereignty resides in the whole (in one people) or in the parts (in many peoples): the federal state (or federation) and the federal union of states (or federal union), respectively. Leading examples of the federal state include the United States, Germany, Canada, Switzerland, Australia and India. The leading example of the federal union of states is the European Union.
ground_truth: 1963
sub_queries: What is an example of a federal union? Answer: the European Union
which country in europe recently voted to leave the European Union Answer: The UK
where are apache helicopters based in the The UK Answer: Britain
when did the beatles become popular in Britain Answer: 1963