1. Canada
   Roman Empire
2. Australia

In the heady days of the Roman Empire, Julius Caesar was a dictator of immense power. But other Romans conspired against him in hopes of restoring a republic, so they assassinated Caesar in one of history’s most famous betrayals.

1. inventor
   fighter pilot
2. king

During World War I, German pilot Manfred Albrecht Freiherr von Richthofen, or simply the Red Baron, became one of the conflict’s deadliest fighters. But in the end, he was killed as he killed — in the air.

1. publishing
   farming
2. computing

Linotype machines of the late 1800s greatly improved the efficiency of publishing, particularly newspapers. The machines made it much easier for people to share information.

1. America
   China
2. United States

Around the year 100, a Chinese man named Cai Lun invented paper and the processes used to make it. Paper, of course, transformed the way people communicated ideas.

1. smallpox
   Black Death
2. AIDS

Around 1350, the plague began sweeping across much of Europe and Asia. The Black Death left incredible numbers of dead in its wake and completely altered societies.

1. sailboats
   Honda Accord
2. gas-fueled engine

In the 1880s, Gottlieb Daimler tested many engine types until he created the first gas-powered engine. His engines would help spark the automobile revolution.

1. Ludwig van Beethoven
   Alexander Hamilton
2. William Shakespeare

At the end of the 1500s, English legend William Shakespeare wrote "Hamlet." It is called an apex in the history of world literature.

1. Continental Army
   Merchant Marine
2. SEALs

George Washington led the Continental Army against the mighty British Army in the Revolution. What started as a group of rough colonists eventually morphed into a well-oiled military machine.

1. British Prime Minister
   Bank of Europe
2. Catholic Church

In 1096, the Pope decided to drive Muslims out of the Holy Lands near Jerusalem, and so, The First Crusade began. Many people died, but no one really won.

1. Laos
   Greece
2. United States

George Washington and Co. had nothing on the Greeks of the 6th century. It was there that the first documented democracy was built, inspiring many nations to reach for liberty in later centuries.

1. gin rummy
   cotton gin
2. gin

In 1793, American Eli Whitney invented the cotton gin, which made it much easier to separate cotton fibers from seeds. His machine jumpstarted the Industrial Revolution in the United States.

1. leprosy
   apartheid
2. space exploration

In South Africa, Mandela was an activist who fought apartheid (racial segregation). He was imprisoned for nearly three decades ... and then became president.

1. Portugal
   Iceland
2. France

President Thomas Jefferson knew a good deal when he saw one. America doubled its territory in the Louisiana Purchase, thanks to the seller ... France, which got just $11 million in return.

1. Gemini 8
   Voyager 2
2. Apollo 11

On July 20, 1969, NASA’s Apollo 11 landed two men on the moon. It was America’s most famous space accomplishment.

1. to kill soldiers
   to move water
2. to make babies

The Archimedes Screw, often attributed to the famous Greek thinker of the 3rd century BC, is a screw pump. It features a large screw inside a pipe, and when the screw is turned, it can move water uphill.

1. South
   North
2. West

In July 1863, both the North and South suffered terribly in the bloody Battle of Gettysburg. The Union won, and the battle became a turning point in the Civil War.

1. Pablo Picasso
   Leonardo da Vinci
2. Vincent van Gogh

In the early 1500s, Leonardo da Vinci created the "Mona Lisa," a painting of a woman with a slight smile. On display at the Louvre in France, it is easily the most famous painting in the history of humankind.

1. Spanish-American War
   World War I
2. American Civil War

One killing turned into millions. In June 1914, a Serbian extremist killed Archduke Franz Ferdinand of Austria, and the murder spiraled into World War I.

1. Mexico
   Japan
2. Brazil

The Empire of the Rising Sun grew to fame in the 20th century in large part due to its military conquest, including the bombing of Pearl Harbor in WWII. The Empire was then bombed to pieces.

1. smokeless gunpowder
   atomic bomb
2. microwaves

He was the guy in charge of the Manhattan Project in WWII. Robert Oppenheimer led Allied scientists in their frantic bid to develop the atomic bomb.

1. John Adams
   John Tyler
2. Gerald Ford

After George Washington served two terms, it was John Adams’ turn to become president. Adams was an odd duck who often conflicted with his peers ... and he lasted just a single term.

1. tires
   horse saddles
2. firearms

In the mid-1800s, Colt created a process to mass manufacture revolvers. His pistols became world famous and made him rich during the Civil War.

1. steam turbine
   solar panels
2. kerosene engine

Parsons invented the steam turbine in 1884. His turbines were great for propelling ships and powering electrical generators.

1. Dark Ages
   Middle Ages
2. Bronze Age

The Bronze Age started roughly around 3300 BC, far before the other ages. It was then that humans first learned to use bronze for things like tools and weapons.

1. Theodore Roosevelt
   Lyndon Johnson
2. Ronald Reagan

In 1965, Lyndon Johnson signed the Voting Rights Act that made it much easier for minority groups to cast their votes. It is frequently called one of the most important federal bills ever signed.

1. toasters
   safer roadways
2. space travel

In the 1930s, Shaw made reflective cat’s eye roadway markers, which are now used all over the world. These markers make it much easier for drivers to see the road in dark conditions.

1. England
   Japan
2. Norway

England’s King James II was cast out of power by the English conspirators and Dutch rivals in the Glorious Revolution. James’ overthrow severely hampered the Catholic Church’s influence.

1. photography
   biology
2. physics

In the 1820s, Daguerre began developing technologies that would lead to photography. He used light-sensitive chemicals to produce daguerreotype, a forerunner of photographs.

1. arson reduction
   metal working
2. home heating

Invented in 1889, industrial electric furnaces transformed metal factories. It made it much easier and cheaper for companies to work with and crank out steel, aluminum, and more.