When Kublai Khan led the Mongols’ conquest of China in the late 1200s, he made Beijing his winter capital. Beijing (also known as Peking) has served as the center of Chinese government almost ever since, and the city’s layout reflects its imperial past. Old Beijing consisted of two adjoining, walled areas known as the Inner City, which contained the Imperial City, and the Outer City. At the heart of the Imperial City lay the Forbidden City, so called because no one outside of the imperial court could enter without permission.

The Forbidden City, largely constructed in the 1400s during the Ming dynasty, contained hundreds of buildings and more than 9,000 rooms. Guarded by moats and towers, it was enclosed by purple walls rising 35 feet and stretching more than two miles on each side. With imposing gateways, marble bridges, terraced courtyards, and glittering yellow-tiled roofs, the Forbidden City radiated majesty.

For nearly 500 years, Chinese emperors used six principal buildings in the Forbidden City. The Three Great Halls were devoted to ceremonial functions: The Hall of Supreme Harmony, which housed the throne; the Hall of Complete Harmony, where policy statements were prepared; and the Hall of Preserving Harmony, where diplomats and scholars were received. The Three Rear Palaces were used for state business and as the imperial family’s quarters.

PostScript: An imperial law prohibited the construction of buildings taller than those in the Forbidden City, which generally were one story high. Under the People’s Republic of China, the Forbidden City buildings have been operated as a public museum since 1949.

In April 1846, a party of 87 pioneers (including 39 children) left Illinois for California by wagon train. The settlers, led by George and Jacob Donner, quickly encountered problems; they quarreled incessantly, and their untested route proved more difficult than anticipated. As a result, the Donner party was delayed by weeks, and only in late October did it reach the Sierra Nevada, a mountain range lying more than 7,000 feet above sea level in northern California. Because of the tragedy that followed, the pass leading through the Sierras now bears the name Donner Pass.

The Donner party found that the mountain pass had been blocked by a snowstorm. The settlers were forced to encamp with limited shelter and food. They used rocks, logs, and animal skins to build cover, and were forced to eat mice, their animals, and even their shoes. Facing starvation, the pioneers ultimately devoured the corpses of their dead companions.

In late December, a group of the snowbound settlers attempted to break through the Sierras on snowshoes. Although several died, seven lived and alerted rescue workers. Four relief parties from Sutter’s Fort (present-day Sacramento) reached the camp between February 22 and April 22, 1847. Only 47 members of the party survived the tragedy at Donner Pass.

PostScript: Twenty-three years after tragedy befell the wagoneering Donner party, the first transcontinental railroad was completed. Its route went through Donner Pass. The pass, now a national historical landmark, today is traversed by rail and highway, and connects Reno with San Francisco.

Following their defeat of German forces in World War II, the Allied nations occupied Germany. They divided the country into four zones, with Britain, France, the Soviet Union, and the United States each controlling one zone. The German capital of Berlin, which lay deep within the Soviet zone of occupation, also was divided into four sectors and ruled jointly by the Allied nations.

The Soviet Union soon disagreed with the democratic Allied nations over the terms for reunifying Germany. By 1950, the border between the Soviet zone of occupation (East Germany) and the non-Soviet zones of occupation (West Germany) was closed. The non-Soviet sectors of Berlin (West Berlin) remained a democratic outpost in East Germany. When West Germany enjoyed an economic resurgence as conditions worsened in East Germany, more than 2.5 million East Germans fled to West Berlin.

To stop this flow of refugees, East German authorities sealed off West Berlin. In 1961, they began construction of the Berlin Wall, which ultimately stretched as a series of concrete walls for more than 100 miles, separating West Berlin from the Soviet-controlled East Berlin and East Germany. Standing as a symbol of the Cold War, the Wall, 15 feet tall in places and topped with barbed wire, was fortified by guards and mines. Nearly 200 people were killed attempting to cross the barricade.

PostScript: Following widespread protests demanding democratic reform, the Communist government of East Germany was forced from power in 1989. The borders opened, and the Berlin Wall fell. Within a year, East Germany and West Germany were reunified as a single nation.

In 1861, Robert E. Lee left his mansion in Arlington County, Virginia, to join the Confederate Army in the Civil War. Union troops soon occupied his estate. Three years later, by government order, the land became a military cemetery. Sprawling over 600 acres along the banks of the Potomac River, Arlington National Cemetery has served ever since as the final resting place for American soldiers, statesmen and heroes.

The mansion, built in 1802, originally was the home of George Washington’s adopted son, whose daughter married Lee. Now known as Arlington House, it is the cemetery’s central landmark. On the grounds, the famous Tomb of the Unknowns stands in memoriam to American soldiers who died in World War I, World War II, the Korean War, and the Vietnam War. The tomb at one time contained the remains of one soldier “known but to God” from each of those wars; in 1998, the remains of the Vietnam casualty were removed and identified through the use of DNA technology.

A sea of stark white headstones marks the graves of the more than 260,000 people laid to rest in the cemetery’s Fields of the Dead. The buried include casualties from every conflict in which the United States has fought. An eternal flame burns at the grave of President John F. Kennedy, the most visited site in the cemetery.

PostScript: After a lengthy court battle, Lee’s eldest son, George Washington Custis Lee, succeeded in declaring that the government had improperly confiscated the land. In 1883, he transferred title to the United States for $150,000.

When Thomas Jefferson failed to find an architect who could build his planned home, Monticello, to his satisfaction, he studied architecture himself. Jefferson was drawn to the works of Andrea Palladio, an architect during the High Renaissance of sixteenth-century Italy. Thus began an American revival of Palladianism, an architectural style named for Palladio and based on his theory that architecture should be grounded in reason and the principles of antiquity. Before the eighteenth century concluded, Palladianism had spread around the world, making Palladio perhaps the most imitated architect in history.

Palladianism expresses its reliance on rationality through symmetry, balance, and harmony of proportion. Palladio paid homage to Greek and Roman antiquity, meanwhile, through the use of decorative motifs, temple fronts, and colonnades; his most copied feature may have been a roofed porch supported by columns. Palladio derived his style primarily from his own reasoning, based on his direct study of Roman ruins.

Palladio applied his principles in more than 140 commissions. The majority of his works have been destroyed or survive only in fragments or drawings; Palladio’s ideas nonetheless have been preserved by his famed treatise, The Four Books of Architecture, which he prepared over the course of more than twenty years.

PostScript: Though less daring than his famed contemporary Michaelangelo, Palladio is considered by many to have been a better architect and has had more widespread influence in that field. As a tribute to his greatness, he is the only architect to have an architectural style named for him.

The identity of the woman with the enigmatic smile in the Leonardo da Vinci masterpiece Mona Lisa baffled generations of researchers. She now is believed to have been Lisa Gherardini, the wife of merchant Francesco del Giocondo of Florence. Leonardo executed the painting, officially titled La Giaconda, during a stay there between 1503 and 1506.

Mona Lisa illustrates Leonardo’s revolutionary style, which earned him praise from his High Renaissance contemporaries. The masterpiece, for example, reveals Leonardo’s exploration of the psychological world. Prior to Leonardo, works of art were judged on their technical portrayal of the physical world; Leonardo, however, insisted that a “figure is most praiseworthy which ... best expresses the passions of the soul,” an aim accomplished by Mona Lisa’s aloof yet seductive smile. Leonardo’s innovative “sfumato” coloring also is present in the painting. By using low-intensity colors and gradual transitions, Leonardo created a hazy, softened atmosphere that seamlessly integrated the central figure with its background.

In 1911, an Italian decorator working at the Louvre in Paris cut Mona Lisa from its frame and removed the painting from the museum under his overalls. When the thief later was caught attempting to sell Mona Lisa, he claimed to have stolen the work in order to restore it to his homeland. In 2005, the Louvre moved Mona Lisa into its own room, built at a cost in excess of $6 million.

PostScript: Leonardo’s student, Andrea Salai, painted a nude version of Mona Lisa in 1515. Art experts believe that Salai’s portrait is a copy of a lost erotic parody by Leonardo himself.

Many prominent American writers and poets of the richly literate 1920s, including F. Scott Fitzgerald, Ernest Hemingway, and e.e. cummings, were described as “lost.” After coming of age during World War I, the “lost generation” had become disillusioned with the values and traditions passed down from previous generations. President Warren G. Harding’s call for a “return to normalcy” following the devastation of war rang spiritually hollow, and America seemed irretrievably provincial and materialistic. Feeling alienated from their home country, the lost generation responded by moving to Paris and living with reckless abandon.

The group gained its designation when Gertrude Stein (one of the original emigres) told Hemingway, “All of you young people who served in the war. You are a lost generation.” Although Hem-ingway originally disapproved of the name, he later used it in the preface to The Sun Also Rises, a novel featuring a cast of hard-drinking, disenchanted expatriates living without faith or direction in postwar Paris. Hemingway’s use of the phrase made it famous.

By 1930, most of the lost generation had returned to America; some were forced to return due to falling stock fortunes. As the members went their separate ways, their works lost the flavor of postwar disillusionment.

PostScript: In 1934, Henry Miller’s Tropic of Cancer depicted what was left of Paris’ formerly brilliant Latin Quarter. Stein lived in Paris until the city came under German occupation in 1940, a prelude to World War II. Hemingway later evoked the magic of his Paris years in his memoir A Moveable Feast.

A confluence of events allowed African-American literature to flourish in the United States in the 1920s. W.E.B. DuBois, a black political leader, had asserted that, in seeking equality, African-Americans should not emulate white conventions but rather embrace their own cultural heritage. Then, during World War I, thousands of African-Americans migrated to northern cities to work in defense plants, a population shift that sparked unprecedented white interest in the African-American lifestyle. Black authors descended upon the Harlem district of New York City to take advantage of a previously unimaginable audience and publishing opportunity.

The writers and poets who participated in the “Harlem Renaissance” did not share a literary philosophy or purpose. They were linked, however, by the common experience of being an African-American, and together they created the first substantial body of literature to explore life from that perspective. While African-American writers previously had imitated white writers, they now expressed, with their own distinctive and vigorous style, the joy and agony of the black American. Above all, they displayed intense pride in their race and heritage.

Jean Toomer’s Cane, a collection of poetry and prose evoking black urban and rural life, generally is considered the movement’s finest accomplishment. Langston Hughes, meanwhile, is its most famous participant, having gained success in virtually every literary form. Although the greatest achievements were in literature, the Harlem Renaissance also included important artists and musicians.

PostScript: The movement ended with the onset of America’s Great Depression, which turned the attention of the Renaissance’s white supporters away from the concerns of African-Americans and toward economics and politics.

In 1871, W.S. Gilbert, a barrister and humorist who had turned to a career as a playwright, was commissioned to write the libretto (or text) for a light opera. A prolific 29-year-old composer named Arthur Sullivan, whose credits already included the famous hymn “Onward, Christian Soldiers,” provided the music. Although this initial collaboration proved unsuccessful, Gilbert and Sullivan proceeded to write 13 more operettas, achieving international acclaim and a popularity that endures to this day.

The Gilbert and Sullivan operas are known for their comic plots and satiric mockery of Victorian manners and the British Empire. The Londoners reached the height of fame in 1878-79 with H.M.S. Pinafore and The Pirates of Penzance, and debuted their most successful work, The Mikado, in 1885. Gilbert’s words were sharp and witty and sparkled with charm and rhyme; Sullivan’s compositions were rich and melodious and displayed a sense of musical parody. The operas also are known as the Savoy Operas, after the theater built for their performance.

Gilbert and Sullivan had contrasting temperaments and differing visions, which led to frequent disagreements. Sullivan aimed to compose a grand opera; Gilbert refused to stray from comic opera. An argument over production costs in 1890 halted their collaboration for three years. After Gilbert and Sullivan reconciled, they produced two final operettas that failed to capture their earlier magic.

PostScript: Sullivan, who struggled with a chronic kidney ailment, died in 1900. Gilbert died in 1911 when, at the age of 74, he suffered a heart attack while trying to save a drowning woman.

German-born composer Ludwig van Beethoven was not even 30 years old and already a favorite of the aristocracy in Vienna when, in the late 1790s, he experienced the onset of deafness. Beethoven initially succumbed to despair and resignation, but then emerged from the crisis, vowing to “seize Fate by the throat.”

Thus began the second of the three loosely defined periods in Beethoven’s career. This middle (or “mature”) period is marked by large and highly dramatic works, which Beethoven apparently intended to serve as metaphors for his own turbulent life. The compositions begin with dissonance and turmoil but reach a triumphant conclusion. They thereby illustrate Beethoven’s faith in ascendancy and his optimistic belief that one could prevail over adversity.

Symphony No. 5 in C minor, composed between 1805 and 1807, is a glowing legacy of the middle period. With its powerful first four notes, “Da da da dum,” the Fifth Symphony is immediately recognizable. Beethoven is believed to have said of the intense first movement, “There Fate knocks at the door.” The symphony then drives toward a jubilant climax that evokes the image of a parade celebrating the defeat of Fate.

Beethoven was completely deaf after 1816.

PostScript: Beethoven’s father, a court musician, tried to establish Ludwig as a child prodigy in the image of Mozart. At 17, Beethoven visited Vienna and played for Mozart, who afterward proclaimed that the young virtuoso would achieve world renown. Five years later, Beethoven left home for Vienna, where he remained until his death in 1827.