Pyramids, Egypt.

Built during a time when Egypt was one of the richest and most powerful civilizations in the world, the pyramids—especially the Great Pyramids of Giza—are some of the most magnificent man-made structures in history.

Their massive scale reflects the unique role that the pharaoh, or king, played in ancient Egyptian society. Though pyramids were built from the beginning of the Old Kingdom to the close of the Ptolemaic period in the fourth century A.D., the peak of pyramid building began with the late third dynasty and continued until roughly the sixth (c. 2325 B.C.).

More than 4,000 years later, the Egyptian pyramids still retain much of their majesty, providing a glimpse into the country's rich and glorious past.

The pyramid's smooth, angled sides symbolized the rays of the sun and were designed to help the king's soul ascend to heaven and join the gods, particularly the sun god Ra.

Soviet Union, Union of Soviet Socialist Republics (USSR).

The Soviet Union, or Union of Soviet Socialist Republics (USSR), was established under Vladimir Lenin and the Communist Party in 1922, after five violent years of revolution and civil war that overturned the imperial regime.

At its height, the country consisted of 15 republics and encompassed nearly one-sixth of the earth's land mass. The USSR underwent massive changes in the 1930s and 1940s during Joseph Stalin’s brutal transformation of Soviet industry and society, which led to the imprisonment and death of millions.

In the decades after World War II, the USSR and non-communist west, locked in a prolonged “Cold War,” repeatedly clashed over communist aggression and expansion in Eastern Europe, Asia and Latin America. In the 1980s, a new spirit of reform, epitomized by Mikhail Gorbachev's programs of glasnost (openness) and perestroika (restructuring), took hold in both the USSR and communist Eastern Europe.

As former satellite nations broke free of Soviet control, individual republics within the USSR also struggled for independence. Unable to withstand these internal changes, the Soviet Union was formally dissolved in December 1991.

At it's height, the USSR extended more than 6,800 miles from east to west, covering 11 of the world's 24 time zones.

The Mafia.

The American Mafia, an Italian-American organized-crime network with operations in cities across the United States, particularly New York and Chicago, rose to power through its success in the illicit liquor trade during the 1920s Prohibition era.

After Prohibition, the Mafia moved into other criminal ventures, from drug trafficking to illegal gambling, while also infiltrating labor unions and legitimate businesses such as construction and New York’s garment industry.

The Mafia’s violent crimes, secret rituals and notorious characters such as Al Capone and John Gotti have fascinated the public and become a part of popular culture.

During the latter part of the 20th century, the government used anti-racketeering laws to convict high-ranking mobsters and weaken the Mafia. However, it remains in business today.

Mafia boss John Gotti (1940-2002) was dubbed the “Teflon Don” for his ability to evade prosecution. However, after mobster Sammy Gravano turned government informant and testified against Gotti, Gotti was convicted on murder and racketeering charges in 1992 and sent to prison, where he died of cancer.

The Nazi Party.

Under the leadership of Adolf Hitler (1889-1945), the National Socialist German Workers' Party, or Nazi Party, grew into a mass movement and ruled Germany through totalitarian means from 1933 to 1945.

Founded in 1919 as the German Workers' Party, the group promoted German pride and anti-Semitism, and expressed dissatisfaction with the terms of the Treaty of Versailles, the 1919 peace settlement that ended World War I (1914-1918) and required Germany to make numerous concessions and reparations.

Hitler joined the party the year it was founded and became its leader in 1921. In 1933, he became chancellor of Germany and his Nazi government soon assumed dictatorial powers.

After Germany's defeat in World War II (1939-45), the Nazi Party was outlawed and many of its top officials were convicted of war crimes related to the murder of some 6 million European Jews during the Nazis' reign.

Sales of Hitler's political autobiography "Mein Kampf," sometimes referred to as the bible of the Nazi Party, made him a millionaire. From 1933 to 1945, free copies were given to every newlywed German couple. After World War II, the publication of "Mein Kampf" in Germany became illegal.

Stonehenge.

For centuries, historians and archaeologists have puzzled over the many mysteries of Stonehenge, the prehistoric monument that took Neolithic builders an estimated 1,500 years to erect.

Located in southern England, it is comprised of roughly 100 massive upright stones placed in a circular layout. Whi1e many modern scholars now agree that Stonehenge was once a burial ground, they have yet to determine what other purposes it served and how a civilization without modern technology—or even the wheel—produced the mighty monument.
Its construction is all the more baffling because, while the sandstone slabs of its outer ring hail from local quarries, scientists have traced the bluestones that make up its inner ring all the way to the Preseli Hills in Wales, some 200 miles from where Stonehenge sits on Salisbury Plain.
Today, nearly 1 million people visit Stonehenge, a UNESCO World Heritage Site since 1986, every year.

In 1620, George Villiers, 1st Duke of Buckingham, dug a large hole in the ground at the center of Stonehenge looking for buried treasure.

Statue of Liberty.

The Statue of Liberty was a joint effort between France and the United States, intended to commemorate the lasting friendship between the peoples of the two nations. The French sculptor Frederic-Auguste Bartholdi created the statue itself out of sheets of hammered copper, while Alexandre-Gustave Eiffel, the man behind the famed Eiffel Tower, designed the statue's steel framework. The Statue of Liberty was then given to the United States and erected atop an American-designed pedestal on a small island in Upper New York Bay, now known as Liberty Island, and dedicated by President Grover Cleveland in 1886.
Over the years, the statue stood tall as millions of immigrants arrived in America via nearby Ellis Island; in 1986, it underwent an extensive renovation in honor of the centennial of its dedication. Today, the Statue of Liberty remains an enduring symbol of freedom and democracy, as well as one of the world's most recognizable landmarks.

The base of the Statue of Liberty's pedestal contains exhibits on the monument's history, including the original 1886 torch. Visitor access to the Statue of Liberty's torch was halted for good after German operatives set off an explosion on the nearby Black Tom peninsula in July 1916, during World War I.

Machu Picchu, Peru.

Tucked away in the rocky countryside northwest of Cuzco, Peru, Machu Picchu is believed to have been a royal estate or sacred religious site for Inca leaders, whose civilization was virtually wiped out by Spanish invaders in the 16th century.
For hundreds of years, until the American archaeologist Hiram Bingham stumbled upon it in 1911, the abandoned citadel’s existence was a secret known only to peasants living in the region. The site stretches over an impressive 5-mile distance, featuring more than 3,000 stone steps that link its many different levels.
Today, hundreds of thousands of people tramp through Machu Picchu every year, braving crowds and landslides to see the sun set over its towering stone monuments and marvel at the mysterious splendor of one of the world's most famous manmade wonders.

Machu Picchu is made up of more than 150 buildings ranging from baths and houses to temples and sanctuaries.