The Four Horsemen of the Apocalypse (1921)

Madariaga "The Centaur" (Pomeroy Cannon), a harsh but popular Argentine landowner, has a German son-in-law, Karl von Hartrott, whom he dislikes and a French one, Marcelo Desnoyers, whose family he openly favors. He is particularly fond of his grandson, Julio (Rudolph Valentino), with whom he often carouses at seedy dives in the Boca district of Buenos Aires. In one of those bars, the movie's famous tango sequence occurs. A man and a woman (Beatrice Dominguez) are dancing the tango. Julio strides up and asks to cut in. The woman stares at Julio alluringly. The man brushes him off, and they resume dancing. Julio then challenges the man, strikes him, and knocks him into some tables and out of the scene. Julio and the woman then dance a dramatic version of the tango that brings cheers from the people in the establishment. After the dance, the woman sits on Julio's lap. Madariaga then drunkingly slides to the floor. The woman laughs at Madariaga. Julio casts her aside in scorn and helps his grandfather home.

Sometime later, Madariaga dies. The extended family breaks up, one half returning to Germany and the other to France.

In Paris, Julio enjoys a somewhat shiftless life as a would-be artist and sensation at the local tea dances. He falls in love with Marguerite Laurier (Alice Terry), the unhappy and much younger wife by an arranged marriage of Etienne Laurier, a friend of Julio's father. The affair is discovered, and Marguerite's husband agrees to give her a divorce to avoid a scandal. It seems as if Julio and Marguerite will be able to marry, but both end up getting caught up in the start of the Great War.

The scene where the man upstairs (Nigel de Brulier) shows Julio (Valentino) and his manservant (Bowditch M. Turner) the Four Horsemen of the Apocalypse.
Marguerite becomes a nurse in Lourdes. The bravery of Etienne is reported, and he is blinded in battle. Etienne happens to end up at the hospital at which she works, and Marguerite attends to him there. Julio travels to Lourdes to see Marguerite but sees her taking care of Etienne. Julio, ashamed of his wastrel life, enlists in the French Army.

In the meantime, the German Army overruns Marcelo's Marne valley castle at the First Battle of the Marne. Marcelo is forced to host a German general and staff in the castle. One of Marcelo's three German nephews is among the staff and tries to protect him, but Marcelo is arrested after a mêlée involving an officer's assault of a woman. Marcello is to be executed in the morning, but his life is spared when the French Army counterattacks during the "Miracle of the Marne". The castle is destroyed by the French counterattack.

Four years later, Julio has survived and become renowned for his bravery in the trenches at the front. During a mission in no man's land, he encounters his last surviving German cousin. Moments later, they are both killed by a shell. Back in Paris, Marguerite considers abandoning the blinded Etienne, but Julio's ghost guides her to continue her care for him.

The ending scene shows Marcelo Desnoyers mourning over his son's grave. The man who lived upstairs from Julio watches over him. Marcelo asks him, "Did you know my son?" The man, with a remorseful expression, lifts his arms, forming the shape of a cross with his body, and says, "I knew them all!" He then points to the sky and shows Marcelo the Four Horsemen of the Apocalypse riding away into the clouds. Then, the man assures him that "Peace has come—but the Four Horsemen will still ravage humanity—stirring unrest in the world—until all hatred is dead and only love reigns in the heart of mankind."