Andrew Jackson (March 15, 1767 – June 8, 1845) was the seventh President of the United States (1829–1837). Based in frontier Tennessee, Jackson was a politician and army general who defeated the Creek Indians at the Battle of Horseshoe Bend (1814), and the British at the Battle of New Orleans (1815). A polarizing figure who dominated the Second Party System in the 1820s and 1830s, as president he destroyed the national bank and relocated most Indian tribes from the Southeast to west of the Mississippi River. His enthusiastic followers created the modern Democratic Party. The 1830–1850 period later became known as the era of Jacksonian democracy.

Jackson was nicknamed "Old Hickory" because of his toughness and aggressive personality; he fought in duels, some fatal to his opponents. He was a rich slaveholder, who appealed to the common men of the United States, and fought politically against what he denounced as a closed, undemocratic aristocracy. He expanded the spoils system during his presidency to strengthen his political base.

World War I (WWI), which was predominantly called the World War or the Great War from its occurrence until 1939 (World War II), and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918. It involved all the world's great powers, which were assembled in two opposing alliances: the Allies (based on the Triple Entente of the United Kingdom, France and Russia) and the Central Powers (originally centred around the Triple Alliance of Germany, Austria-Hungary and Italy; but, as Austria–Hungary had taken the offensive against the agreement, Italy did not enter into the war). These alliances both reorganised (Italy fought for the Allies), and expanded as more nations entered the war. Ultimately more than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history. More than 9 million combatants were killed, largely because of enormous increases in lethality of weapons, thanks to new technology, without corresponding improvements in protection or mobility. It was the sixth-deadliest conflict in world history, subsequently paving the way for various political changes such as revolutions in the nations involved.

Mexican Americans are Americans of Mexican descent. As of July 2009, Mexican Americans make up 10.3% of the United States' population with over 31,689,000 Americans listed as of Mexican ancestry. Mexican Americans comprise 66% of all Hispanics and Latinos in the United States. The United States is home to the second largest Mexican community in the world second only to Mexico itself comprising nearly 22% of the entire Mexican origin population of the world. Canada is a distant third with a Mexican origin population of 37,000 as of 2001 although increasing to 61,505 as of 2006. In addition, as of 2008 there were approximately 7,000,000 undocumented Mexicans living in the United States which if included in the count would increase the US share to over 28% of the world's Mexican origin population (Note that some of the undocumented would be captured in the US Census count depending on their willingness to provide information). Over 60% of all Mexican Americans reside in the states of California and Texas. Most Mexican Americans are the descendants of the Indigenous peoples of Mexico and/or Europeans, especially Spaniards.