What was the first horror movie ever made?Well, that depends on your definition of what is a horror movie.
If we're talking about fully scripted movies, with actors, ghoulish characters, 'scary' effects and whatnot involved then the answer would have to be Le manoir du diable (The House of the Devil), from 1896, by French director Georges Méliès (yes, that guy from Martin Scorsese's 2011 movie Hugo). A vampire(!) themed (along with many other different horror themes) short, that stars Georges Méliès himself, along with other. Méliès is considered to be the "The Father of Special Effects" so it would only make sense for this person to be responsible for the very first horror movie, full with scary effects, as well.
However if we dig even deeper and go back even further in time, to 1895, we come across a movie that portrays a historical, horror-like, event; the beheading of Mary, Queen of Scots, in 1567 (no cameras around then...).
The 15 seconds short is known under several different titles, such as The Execution of Mary Stewart, Execution of Mary, Queen of Scots and this simply Execution. It was made by non other than Thomas Edison. Of course most people know Edison as the inventor of the light bulb, along with a whole bunch of other world changing inventions. One of those inventions was his version of the motion picture camera, known as the Kinetograph. With this invention, Edison made close to 1,200 shorts, each often about different subjects, most shot inside Edison's Black Maria studios in West Orange, New Jersey.
The short itself was directed by Alfred Clark, who only directed an handful of shorts for Edison around the time and this particular short actually was the very first one Clark had ever directed, with William Heise operating the camera. The role of Mary funny enough got played by a man, named Robert Thomae and it stars a bunch of other, unknown, actors as extras and the executioner.
Thanks to the wonders of modern technology and the interwebs both shorts have been immortalized and are nowadays available for everyone to watch. Totally for free and legally of course! It's both fun and interesting to watch these shorts in today's perspective, as it provides us with the earliest look possible into the widely known- and still immensely popular, horror genre.
Have a look at both shorts:
Le Manoir du Diable (1896)