Joseph Conrad’s 1899 novella about venturing into the moral depths of colonial Africa is among the most frequently analyzed literary works in college curricula.

1. ENGLISH WAS THE AUTHOR’S THIRD LANGUAGE.

It’s impressive enough that Conrad wrote a book that has stayed relevant for more than a century. This achievement seems all the more impressive when considering that he wrote it in English, his third language. Born Józef Teodor Konrad Korzeniowski in 1857, Conrad was a native Polish speaker. French was his second language. He didn’t even know any English—the language of his literary composition—until age 21.

2. HEART OF DARKNESS BEGINS AND ENDS IN THE UK.

Though it recounts Marlow's voyage through Belgian Congo in search of Kurtz and is forever linked to the African continent, Conrad’s novella begins and ends in England. At the story’s conclusion, the “tranquil waterway” that “seemed to lead into the heart of an immense darkness” is none other than the River Thames.

3. THE PROTAGONIST MARLOW IS CONRAD.

The well-traveled Marlow—who appears in other Conrad works, such as Lord Jim—is based on his equally well-traveled creator. In 1890, 32-year-old Conrad sailed the Congo River while serving as second-in-command on a Belgian trading company steamboat. As a career seaman, Conrad explored not only the African continent but also ventured to places ranging from Australia to India to South America.

4. LIKE KURTZ AND MARLOW, CONRAD GOT SICK ON HIS VOYAGE.

Illness claimed Kurtz, an ivory trader who has gone mysteriously insane. It nearly claimed Marlow. And these two characters almost never existed, owing to their creator’s health troubles. Conrad came down with dysentery and malaria in Belgian Congo, and afterwards had to recuperate in the German Hospital, London, before heading to Geneva, Switzerland, to undergo hydrotherapy. Though he survived, Conrad suffered from poor health for many years afterward.

5. THERE HAVE BEEN MANY ALLEGED KURTZES IN REAL LIFE.

The identity of the person on whom Conrad based the story’s antagonist has aroused many a conjecture. Among those suggested as the real Kurtz include a French agent who died on board Conrad’s steamship, a Belgian colonial officer, and Welsh explorer Henry Morton Stanley.

6. COLONIZING WAS ALL THE RAGE WHEN HEART OF DARKNESS APPEARED.

Imperialism—now viewed as misguided, oppressive, and ruthless—was much in vogue when Conrad’s novella hit shelves. The "Scramble for Africa" had seen European powers stake their claims on the majority of the continent. Britain’s Queen Victoria was even portrayed as the colonies' "great white mother." And writing in The New Review in 1897, adventurer Charles de Thierry (who tried and failed to establish his own colony in New Zealand) echoed the imperialistic exuberance of many with his declaration: “Since the wise men saw the star in the East, Christianity has found no nobler expression.”

7. CHINUA ACHEBE WAS NOT A FAN OF THE BOOK.

Even though Conrad was no champion of colonialism, Chinua Achebe—the Nigerian author of Things Fall Apart and other novels—delivered a 1975 lecture called “An Image of Africa: Racism in Conrad’s Heart of Darkness” that described Conrad as a “thoroughgoing racist” and his ubiquitous short classic as “an offensive and deplorable book.” However, even Achebe credited Conrad for having “condemned the evil of imperial exploitation.” And others have recognized Heart of Darkness as an indictment of the unfairness and barbarity of the colonial system.

8. THE BOOK WASN’T SUCH A BIG DEAL—AT FIRST.

In 1902, three years after its initial serialization in a magazine, Heart of Darkness appeared in a volume with two other Conrad stories. It received the least notice of the three. In fact, not even Conrad himself considered it a major work. And during his lifetime, the story “received no special attention either from readers or from Conrad himself,” writes Gene M. Moore in the introduction to Joseph Conrad's Heart of Darkness: A Casebook. But Heart of Darkness managed to ascend to immense prominence in the 1950s, after the planet had witnessed “the horror”—Kurtz's last words in the book—of WWII and the ramifications of influential men who so thoroughly indulged their basest instincts.

9. T.S. ELIOT BORROWED AN IMPORTANT LINE.

Though Heart of Darkness wasn’t an immediate sensation, it evidently was on the radar of some in the literary community. The famous line announcing the antagonist’s demise, “Mistah Kurtz—he dead,” serves as the epigraph to the 1925 T.S. Eliot poem “The Hollow Men.”

10. THE STORY INSPIRED APOCALYPSE NOW.

Eighty years after Conrad’s novella debuted, the Francis Ford Coppola film Apocalypse Now hit the big screen. Though heavily influenced by Heart of Darkness, the movie’s setting is not Belgian Congo, but the Vietnam War. And though the antagonist (played by Marlon Brando) is named Kurtz, this particular Kurtz is no ivory trader, but a U.S. military officer who has become mentally unhinged.

11. HEART OF DARKNESS HAS BEEN MADE INTO AN OPERA.

Tarik O'Regan’s Heart of Darkness, an opera in one act, opened in 2011. Premiering at London’s Royal Opera House, it was reportedly the first operatic adaptation of Conrad’s story and heavily inspired by Apocalypse Now.

12. THE BOOK ALSO SPARKED A VIDEO GAME.

In a development not even Conrad’s imagination could have produced, his classic inspired a video game, Spec Ops: The Line, which was released in 2012.