The Last Egyptian (partially found silent film; 1914)
The Last Egyptian was originally a novel written under a pseudonym of L. Frank Baum who was more famous for creating the Wizard of Oz series, it centered around three main characters: an Egyptian named Kara, the historian Gerald Winston Bey and the Dragoman Tadros. The book follows their journey to find a tomb filled with treasure belonging to the Princess Hatatcha with the story coming to a dramatic conclusion when Kara is trapped inside the tomb he'd kept revisiting to steal more loot after a failed attempt to kill Winston and several others, including a man named Rodger who inadvertently traps him inside the tomb when he dislodges the object holding the door open as he flees.
Though the book was published under a false name, the movie adaptation was eventually released under the Oz name with the Baum name attached. However, due to other recent film flops in the Oz film series, the association turned off many would-be filmgoers and the film company was bought out by Metro with any surviving prints held by the company likely destroyed either shortly after the buyout or during the infamous 1965 MGM archive fire which devastated the company's holdings of pre-1924 films (and some films made after 1924 as well).
While the filmmaker Bill Morrison was making his experimental art film Decasia he trawled through many film archives to locate interesting deteriorating nitrate footage and one decomposing reel was a surviving reel from The Last Egyptian. When the film was put out, an L. Frank Baum expert was notified after the clip was identified, and with the help of Bill Morrison, they were able to go to the Museum of Modern Art where the footage had originated and three out of the five reels of the feature film were located in their holdings. After this discovery, the surviving reels were eventually displayed in an Oz festival in 2008.