Baby boomers in the context of "Post–World War II baby boom"

Population momentum or demographic inertia is the tendency of the raw birth rate to rise as a result of past high fertility rates, even after fertility rates have fallen, or vice-versa. This occurs because a current increase in fertility rates causes an increase in the number of women of childbearing age roughly twenty-to-forty years later, meaning population growth figures tend to lag substantially behind fertility rates. Well-known examples include the Echo Boom (the increase in the total number of births as baby boomers reached child-rearing age) and Chinese population growth throughout the era of the one-child policy (from 1979 until 2021).

Population momentum explains why a population will continue to grow even if the fertility rate declines or continues to decline even if the fertility rate grows. Population momentum occurs because it is not only the number of children per woman that determine population growth, but also the number of women of reproductive age. Eventually, when the fertility rate reaches the replacement rate and the population size of women in the reproductive age bracket stabilizes, the population achieves equilibrium and population momentum comes to an end. Population momentum is defined as the ratio of the size of the population at that new equilibrium level to the size of the initial population.

The middle of the 20th century was marked by a significant and persistent increase in fertility rates in many countries, especially in the Western world. The term baby boom is often used to refer to this particular boom, generally considered to have started immediately after World War II, although some demographers place it earlier or during the war. This terminology led to those born during this baby boom being nicknamed the baby boom generation.

The boom coincided with a marriage boom. The increase in fertility was driven primarily by a decrease in childlessness and an increase in parity progression to a second child. In most of the Western countries, progression to a third child and beyond declined, which, coupled with aforementioned increase in transition to first and second child, resulted in higher homogeneity in family sizes. The baby boom was most prominent among educated and economically active women.

Millennials, also known as Generation Y or Gen Y, are the demographic cohort following Generation X and preceding Generation Z. Researchers and popular media use the early 1980s as starting birth years and the mid-1990s to early 2000s as ending birth years, with the generation typically being defined as people born from 1981 to 1996. Most millennials are the children of baby boomers and older Gen Xers, and are often the parents of Generation Alpha.

As children in the late 1980s to 2000s, millennials saw the rise of the Information Age and Internet, being described by some as the first global generation. As adolescents and young adults in the late 1990s to 2010s, the generation was marked by a more upbeat youth culture, elevated familiarity with the Internet and technology in general, and usage of early social media platforms such as AOL Instant Messenger, LiveJournal, and Myspace. Between the 1990s and 2010s, people from developing countries became increasingly well-educated, a factor that boosted economic growth in these countries.

The Sun Belt is a region of the United States generally considered stretching across the Southeast and Southwest. Another rough definition of the region is the area south of the Parallel 36°30′ north. Several climates can be found in the region—desert/semi-desert (Eastern California, Nevada, Arizona, New Mexico, Utah, and West Texas), Mediterranean (California), humid subtropical (Alabama, Mississippi, Louisiana, Florida, Georgia, South Carolina, North Carolina, Arkansas,Tennessee and Texas), and tropical (South Florida).

The Sun Belt has seen substantial population growth post-World War II from an influx of people seeking a warm and sunny climate, a surge in retiring baby boomers, and growing economic opportunities. The advent of air conditioning created more comfortable summer conditions and allowed more manufacturing and industry to locate in the Sun Belt. Since much of the construction in the Sun Belt is new or recent, housing styles and design are often modern and open. Recreational opportunities in the Sun Belt are often not tied strictly to one season, and many tourist and resort cities in the region support a tourist industry all year.

The protests of 1968 comprised a worldwide escalation of social conflicts, which were predominantly characterized by the rise of left-wing politics, anti-war sentiment, civil rights urgency, youth counterculture within the Silent and baby boomer generations, and popular rebellions against military states and bureaucracies.

In the United States, the protests marked a turning point for the civil rights movement, which produced revolutionary movements like the Black Panther Party. In reaction to the Tet Offensive, protests also sparked a broad movement in opposition to the Vietnam War all over the United States as well as in London, Paris, Berlin and Rome. Mass movements grew in the United States but also elsewhere. In most Western European countries, the protest movement was dominated by students.

The Beatles were an English rock band formed in Liverpool in 1960. The core lineup of the band comprised John Lennon, Paul McCartney, George Harrison and Ringo Starr. They are widely regarded as the most influential band in popular music and were integral to the development of 1960s counterculture and the recognition of popular music as an art form. Rooted in skiffle, beat and 1950s rock 'n' roll, their sound incorporated elements of classical music and traditional pop in innovative ways. The band also explored music styles ranging from folk and Indian music to psychedelia and hard rock. As pioneers in recording, songwriting and artistic presentation, the Beatles revolutionised many aspects of the music industry and were often publicised as leaders of the era's youth and sociocultural movements.

Led by primary songwriters Lennon and McCartney, the Beatles evolved from Lennon's previous group, the Quarrymen, and built their reputation by playing clubs in Liverpool and Hamburg, Germany, starting in 1960. The core trio of Lennon, McCartney and Harrison, together since 1958, went through a succession of drummers before inviting Starr to join them in 1962. Manager Brian Epstein moulded them into a professional act, and producer George Martin developed their recordings, greatly expanding their domestic success after they signed with EMI and achieved their first hit, "Love Me Do", in late 1962. As their popularity grew into the intense fan frenzy dubbed "Beatlemania", the band acquired the nickname "the Fab Four". By early 1964, the Beatles were international stars and had achieved unprecedented levels of critical and commercial success. They became a leading force in Britain's cultural resurgence, ushering in the British Invasion of the United States pop market. They soon made their film debut with A Hard Day's Night (1964).

The English rock band the Beatles, comprising John Lennon, Paul McCartney, George Harrison and Ringo Starr, are commonly regarded as the foremost and most influential band in popular music history. They sparked the "Beatlemania" phenomenon in 1963, gained international superstardom in 1964, and remained active until their break-up in 1970. Over the latter half of the decade, they were often viewed as orchestrators of society's developments. Their recognition concerns their effect on the era's youth and counterculture, British identity, popular music's evolution into an art form, and their unprecedented following.

Many cultural movements of the 1960s were assisted or inspired by the Beatles. In Britain, their rise to prominence signalled the youth-driven changes in postwar society, with respect to social mobility, teenagers' commercial influence, and informality. They spearheaded the shift from American artists' global dominance of rock and roll to British acts (known in the US as the British Invasion) and inspired young people to pursue music careers. From 1964 to 1970, the Beatles had the top-selling US single one out of every six weeks and the top-selling US album one out of every three weeks. In 1965, they were awarded MBEs, the first time such an honour was bestowed on a British pop act. A year later, Lennon controversially remarked that the band were "more popular than Jesus now".

The Silent Generation, also known as the Traditionalist Generation or Builders Generation, is a description mainly in the United States for the demographic cohort following the Greatest Generation and preceding the baby boomers. The generation is generally defined as people born from 1928 to 1945. By this definition and U.S. census data, there were 23 million people from the Silent Generation in the United States as of 2019.

In the United States, the Great Depression of the 1930s and World War II in the early-to-mid 1940s caused people to have fewer children and as a result, the generation is comparatively small. It includes most of those who fought during the Korean War. Upon coming of age in the postwar era, Silents were sometimes characterized as trending towards conformity and traditionalism, as well as comprising the "silent majority". However, they have also been noted as forming the leadership of the civil rights movement and the 1960s counterculture, and creating the rock and roll music of the 1950s and 1960s.