A German-born theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics).

A German-born theoretical physicist who developed the "Theory of Relativity".

An Austrian neurologist and the founder of psychoanalysis, a clinical method for treating psychopathology through dialogue between a patient and a psychoanalyst.

An Austrian neurologist and the founder of psychoanalysis, a clinical method for treating psychopathology through dialogue between a patient and a psychoanalyst.

An Austrian neurologist and the founder of psychoanalysis, a clinical method for treating psychopathology through dialogue between a patient and a psychoanalyst.

A German philosopher, cultural critic, poet, philologist, and Latin and Greek scholar whose work has exerted a profound influence on Western philosophy and modern intellectual history. He began his career as a classical philologist before turning to philosophy. He became the youngest ever to hold the Chair of Classical Philology at the University of Basel in 1869, at the age of 24.

A German philosopher, cultural critic, poet, philologist, and Latin and Greek scholar whose work has exerted a profound influence on Western philosophy and modern intellectual history. He began his career as a classical philologist before turning to philosophy. He became the youngest ever to hold the Chair of Classical Philology at the University of Basel in 1869, at the age of 24.

A German philosopher, cultural critic, poet, philologist, and Latin and Greek scholar whose work has exerted a profound influence on Western philosophy and modern intellectual history. He began his career as a classical philologist before turning to philosophy. He became the youngest ever to hold the Chair of Classical Philology at the University of Basel in 1869, at the age of 24.

An American aviator, military officer, author, inventor, explorer, and environmental activist. At age 25 in 1927 he went from obscurity as a U.S. Air Mail pilot to instantaneous world fame by making his Orteig Prize–winning nonstop flight from Long Island, New York, to Paris.

An American aviator, military officer, author, inventor, explorer, and environmental activist. At age 25 in 1927, he went from obscurity as a U.S. Air Mail pilot to instantaneous world fame by making his Orteig Prize–winning nonstop flight from Long Island, New York, to Paris.

An American aviator, military officer, author, inventor, explorer, and environmental activist. At age 25 in 1927, he went from obscurity as a U.S. Air Mail pilot to instantaneous world fame by making his Orteig Prize–winning nonstop flight from Long Island, New York, to Paris.

The theory transformed theoretical physics and astronomy during the 20th century, superseding a 200-year-old theory of mechanics created primarily by Isaac Newton. It introduced concepts including spacetime as a unified entity of space and time, relativity of simultaneity, kinematic and gravitational time dilation, and length contraction. In the field of physics, relativity improved the science of elementary particles and their fundamental interactions, along with ushering in the nuclear age. With relativity, cosmology and astrophysics predicted extraordinary astronomical phenomena such as neutron stars, black holes, and gravitational waves

A cultural movement that began in the early 1920s, and is best known for its visual artworks and writings. These types of works feature the element of surprise, unexpected juxtapositions and non sequitur; however, many of these artists and writers regard their work as an expression of the philosophical movement first and foremost, with the works being an artifact.

A term applied to the work of certain late-19th- and 20th-century European philosophers who, despite profound doctrinal differences, shared the belief that philosophical thinking begins with the human subject—not merely the thinking subject, but the acting, feeling, living human individual. While the predominant value of this philosophy is commonly acknowledged to be freedom, its primary virtue is authenticity.

A music genre that originated amongst African Americans in New Orleans, United States, in the late 19th and early 20th centuries, and developed from roots in Blues and Ragtime. Since the 1920s jazz age, jazz has become recognized as a major form of musical expression.

an American statesman and political leader who served as the 32nd President of the United States from 1933 until his death in 1945. A Democrat, he won a record four presidential elections and emerged as a central figure in world events during the mid-20th century. He directed the United States government during most of the Great Depression and World War II. As a dominant leader of his party, he built the New Deal Coalition, realigning American politics. He is often rated by scholars as one of the three greatest U.S. Presidents, along with George Washington and Abraham Lincoln

an American statesman and political leader who served as the 32nd President of the United States from 1933 until his death in 1945. A Democrat, he won a record four presidential elections and emerged as a central figure in world events during the mid-20th century. He directed the United States government during most of the Great Depression and World War II. As a dominant leader of his party, he built the New Deal Coalition, realigning American politics. He is often rated by scholars as one of the three greatest U.S. Presidents, along with George Washington and Abraham Lincoln

an American statesman and political leader who served as the 32nd President of the United States from 1933 until his death in 1945. A Democrat, he won a record four presidential elections and emerged as a central figure in world events during the mid-20th century. He directed the United States government during most of the Great Depression and World War II. As a dominant leader of his party, he built the New Deal Coalition, realigning American politics. He is often rated by scholars as one of the three greatest U.S. Presidents, along with George Washington and Abraham Lincoln.

an Italian politician, journalist, and leader of the National Fascist Party, ruling the country as Prime Minister from 1922 to 1943. He ruled constitutionally until 1925, when he dropped all pretense of democracy and set up a legal dictatorship. Known as Il Duce (The Leader), this person was the founder of Italian Fascism.

an Italian politician, journalist, and leader of the National Fascist Party, ruling the country as Prime Minister from 1922 to 1943. He ruled constitutionally until 1925, when he dropped all pretense of democracy and set up a legal dictatorship. Known as Il Duce (The Leader), this person was the founder of Italian Fascism.

an Italian politician, journalist, and leader of the National Fascist Party, ruling the country as Prime Minister from 1922 to 1943. He ruled constitutionally until 1925, when he dropped all pretense of democracy and set up a legal dictatorship. Known as Il Duce (The Leader), he was the founder of Italian Fascism.

a German politician who was the leader of the Nazi Party, Chancellor of Germany from 1933 to 1945, and Führer ("Leader") of Nazi Germany from 1934 to 1945. As dictator of the German Reich, he initiated World War II in Europe with the invasion of Poland in September 1939 and was central to the Holocaust.

a German politician who was the leader of the Nazi Party, Chancellor of Germany from 1933 to 1945, and Führer ("Leader") of Nazi Germany from 1934 to 1945. As dictator of the German Reich, he initiated World War II in Europe with the invasion of Poland in September 1939 and was central to the Holocaust.

a German politician who was the leader of the Nazi Party, Chancellor of Germany from 1933 to 1945, and Führer ("Leader") of Nazi Germany from 1934 to 1945. As dictator of the German Reich, he initiated World War II in Europe with the invasion of Poland in September 1939 and was central to the Holocaust.

a Spanish general who ruled over Spain as a military dictator for 36 years from 1939 until his death.

a Spanish general who ruled over Spain as a military dictator for 36 years from 1939 until his death.

a Spanish general who ruled over Spain as a military dictator for 36 years from 1939 until his death.

a cabinet of a parliamentary government in which several political parties cooperate, reducing the dominance of any one party within that coalition. The usual reason given for this arrangement is that no party on its own can achieve a majority in the parliament. A coalition government might also be created in a time of national difficulty or crisis (for example, during wartime or economic crisis) to give a government the high degree of perceived political legitimacy or collective identity it desires while also playing a role in diminishing internal political strife.

A national assembly , where a new constitution for the Deutsches Reich was written, and adopted on 11 August 1919. In its fourteen years, this assembly faced numerous problems, including hyperinflation, political extremism (with paramilitaries – both left- and right-wing); and contentious relationships with the victors of the First World War. The people of Germany blamed this assembly rather than their wartime leaders for the country's defeat and for the humiliating terms of the Treaty of Versailles

A national assembly , where a new constitution for the Deutsches Reich was written, and adopted on 11 August 1919. In its fourteen years, this assembly faced numerous problems, including hyperinflation, political extremism (with paramilitaries – both left- and right-wing); and contentious relationships with the victors of the First World War. The people of Germany blamed this assembly rather than their wartime leaders for the country's defeat and for the humiliating terms of the Treaty of Versailles

a series of programs, including, most notably, Social Security, that was enacted in the United States between 1933 and 1938, and a few that came later. They included both laws passed by Congress as well as presidential executive orders during the first term (1933–37) of President Franklin D. Roosevelt. The programs were in response to the Great Depression and focused on what historians refer to as the "3 Rs", Relief, Recovery, and Reform: relief for the unemployed and poor, recovery of the economy to normal levels, and reform of the financial system to prevent a repeat depression.

A form of radical authoritarian nationalism that came to prominence in early 20th-century Europe. The first of these movements emerged in Italy during World War I, before it spread to other European countries. Opposed to liberalism, Marxism, and anarchism, this ideology is usually placed on the far-right within the traditional left-right spectrum

a severe worldwide economic depression that took place during the 1930s. The timing of this event varied across nations; in most countries it started in 1929 and lasted until the late 1930s. It was the longest, deepest, and most widespread depression of the 20th century.

In a political context, it is a diplomatic policy of making political or material concessions to an enemy power in order to avoid conflict.

The foreign policy position that a nation's interests are best served by keeping the affairs of other countries at a distance.

the period in German history from 1933 to 1945, when Germany was governed by a dictatorship under the control of Adolf Hitler and the Nazi Party (NSDAP)

Usually characterized as a form of fascism that incorporates scientific racism and antisemitism, this ideology developed out of the influences of Pan-Germanism, the Völkisch German nationalist movement, and the anti-communist Freikorps paramilitary groups that emerged during the Weimar Republic after the German defeat in World War I.

is a 1925 autobiographical book by Nazi Party leader Adolf Hitler. The work outlines Hitler's political ideology and future plans for Germany. Volume 1 was published in 1925 and Volume 2 in 1926. The book was edited by Hitler's deputy Rudolf Hess

Following Adolf Hitler's rise to power this term became an ideological principle of Nazism and provided justification for the German territorial expansion into East-Central Europe. 

are Also known as the Rome–Berlin–Tokyo Axis, were the nations that fought in World War II against the Allied Powers. The Axis agreed on their opposition to the Allies but did not completely coordinate their activity.

A settlement permitting Nazi Germany's annexation of portions of Czechoslovakia along the country's borders mainly inhabited by German speakers, for which a new territorial designation "Sudetenland" was coined. The agreement was signed in the early hours of 30 September 1938 (but dated 29 September) after being negotiated at a conference held in Munich, Germany, among the major powers of Europe, excluding the Soviet Union. Today, it is widely regarded as a failed act of appeasement toward Germany. The purpose of the conference was to discuss the future of the Sudetenland in the face of ethnic demands made by Adolf Hitler.