Warning: Contains spoilers.

Eighty years since its first release, Casablanca continues to regale audiences.

It was called the jewel of Hollywood's Golden Age and was the result of the combined efforts of virtuoso talents in their prime form delivering their very best.

The 1944 Academy Award–winning classic was based on Murray Burnett's and Joan Alison's unproduced play, "Everybody Comes to Rick's," written in 1940, prior to the entry of the United States into World War II.

The rights were bought by Warner Bros. for $20,000, a unprecedented amount for an unproduced play at that time.

Legendary film producer Hal B. Wallis greenlit the picture, which was adapted to the screen by talents such as the twin-brother team Julius and Philip Epstein, who worked on the overall structure and dialogue; screenwriter Howard Koch, who worked on the politics; and Casey Robinson, who worked on the romantic aspects.

Filmmaker Michael Curtiz, known for his visual style, where he employed diffused lighting, extensive and fluid camera movement, and high crane shots, brought the film to life on the big screen.  Curtiz is the reason the film excels both as an intimate story and as an epic, mounted on a large scale.

The evocative score by Max Steiner seamlessly blended the diverse themes across the film, including the French national anthem.  The cinematographer Arthur Edeson deserves plaudits for the myriad iconic visuals, and so does editor Owen Marks for keeping the pace brisk without sacrificing the movie's quality as a work of art.

Living their characters were Humphrey Bogart and Ingrid Bergman as star-crossed lovers.  Both deliver nuanced and understated performances.  It often is very subtle, so much conveyed without uttering a word.  This was a rarity for its time, where the acting was often theatric.

Paul Henreid as Victor Laszlo and Claude Rains as Captain Louis Renault also deliver ably, adding gravitas to the proceedings.  The magnificent Sidney Greenstreet, who plays Casablanca's most notorious black marketer and the owner of the Blue Parrot Café, was also in his usually terrific form.  Peter Lorre, who was Greenstreet's frequent on-screen collaborator, also did very well in a brief role of a shady black marketer.  Dooley Wilson played Rick's black nightclub singer as well as Rich's confidant and ally.

It is hard to pin Casablanca down to any genre.

It is an enthralling World War II spy thriller that keeps you on the edge of your seat throughout.  It also depicts one of the most poignant and heartbreaking love stories ever seen on celluloid.

In addition to the story of its protagonists, Casablanca also tells myriad other human stories of refugees eager to escape persecution, making it a compelling drama. 

There was the darkness of that era, and the specter of doom perennially looming over the world, which is the trademark of film noir, which never leaves this film.

At one point in Casablanca, the Nazis begin singing Die Wacht am Rhein, much to the annoyance of the French refugees and other refugees.  In an act of defiance, the refugees begin singing La Marseillaise, and soon the Germans are drowned out.  This perfectly summarizes what the film stands for.

A compelling film could have been made on any of these elements.  What was remarkable was that they were all in the same film, and the confluence seemed natural.

At its core, this is a film about honor, loyalty, patriotism, sacrifice, friendship, and duty.

Bergman's Elsa sacrifices the love of her life to stand by her man — a leader of the resistance movement against the Nazis.

Bogart's Rick, who is proud of not sticking his neck out for anybody, eventually sacrifices the love of his life and places his life in peril for the greater good.

It was said that Bogart's character was a metaphor for America, which initially seemed reluctant to intervene in World War II, a conflict that seemed irrelevant since it was occurring in a faraway land.  But America entered into the conflict, sacrificed a great deal, and changed the course of the war.

America represents freedom and hope for the people who have fled persecution and death to reach the city of Casablanca, from where refugees would go to Lisbon and then to the "new world": America.

In fact, several of the cast members were European Jewish actors, such as Peter Lorre, Marcel Dalio, and Conrad Veidt, who played a Nazi major who came to America to escape Nazi persecution in Europe.

Much like the occurrences on screen, the production of this film was turbulent.

There were multiple rewrites.  In fact, the ending of the film wasn't written until the last phase of production, causing on-set rows among the filmmaker, the writers, and the cast members.  Perhaps this uncertainty off-screen enabled the actors to convey the uncertainty on screen.

The film won Oscars for Best Picture, Best Director, and Best Adapted Screenplay in 1944.  The film ranked second on the AFI's 100 Greatest American Movies of All Time, the first being Citizen Kane.  Six lines from Casablanca appeared in the Top 100 Movie Quotations list by the American Film Institute.

There are many elements of the film that have been adopted by modern filmmakers.

The film certainly inspired Woody Allen to write the play "Play It Again, Sam," which was eventually made into a movie.  The film begins with Allen watching Casablanca at the cinema.  He is so influenced by it that he hallucinates receiving advice from Bogart, dressed in a trench coat, on how to deal with women.

Bogart's entry with him in a tux and the focus on his hands and his eventual smoking a cigarette probably inspired Sean Connery's first appearance as 007 in the James Bond series.

Bogart's Rick probably inspired Harrison Ford's Han Solo in the Star Wars pictures.  Both were cynical anti-heroes with a wry sense of humor.  Both claimed to be self-centered, yet their heart and moral compass is in the right place, causing them to do the right thing in the end.

Casablanca probably influenced another Harrison Ford film series: the Indiana Jones series, both films had their protagonists taking on the Nazis at the back of World War II in the desert.  A lot of the visuals in the Indy films were similar to those of Casablanca.  Steven Spielberg, who directed the Indy films, is an admirer of Casablanca. 

So is Casablanca a cinematic masterpiece?

We live in an era of extremes, with limitless blandishments and unending brickbats lavished in equal measures, often on undeserving objects.

Audiences step out of the cinema hall, fresh from their senses being overwhelmed by their viewing experience, to say they have watched an "absolute masterpiece."

A fortnight later, there is little memory of the "masterpiece."  That epithet has been transferred to the latest Netflix series binged-watched the previous night.

So how exactly does one judge a cinematic masterpiece?

If a film consumes your mind and your heart during the first viewing and continues to do so upon subsequent viewings, not just months and years, but decades, later, then it is likely to be a masterpiece.  Masterful films are rich with themes, subtext, and motifs that are discovered with each viewing.

Casablanca certainly is that in every way and therefore can safely be called a masterpiece.

Image: Screen shot via shareable YouTube.