Question: What film by the well-known Russian film director who directed silent films such as "Strike (1925), and "Battleship Potemkin(1925) was based on the true story of Pavlik Morozov and thought to have been destroyed before its completion?

Context articles: A Spectre Haunts Europe
Bezhin Meadow
Sergei Eisenstein
Calcutta Film Society
Scapa Flow (film)
Battleship Potemkin (album)
Enno Patalas
Edmund Meisel
Strike (1925 film)
Russian battleship Potemkin

A Spectre Haunts Europe (Russian: Призрак бродит по Европе , "Prizrak brodit po Evrope " ) is a 1923 Soviet silent horror film directed by Vladimir Gardin.
 It was made by the Ukrainian Soviet Socialist Republic's production company VUFKU.
 It is based on Edgar Allan Poe's story "The Masque of the Red Death".
 The film features a massacre on the Odessa Steps which may have served as an inspiration for the more famous scene in Sergei Eisenstein's "Battleship Potemkin".
Bezhin Meadow ("Бежин луг" , "Bezhin lug ") is a 1937 Soviet film famous for having been suppressed and believed destroyed before its completion.
 Directed by Sergei Eisenstein, it tells the story of a young farm boy whose father attempts to betray the government for political reasons by sabotaging the year's harvest and the son's efforts to stop his own father to protect the Soviet state, culminating in the boy's murder and a social uprising.
 The film draws its title from a story by Ivan Turgenev, but is based on the life of Pavlik Morozov, a young Russian boy who became a political martyr following his death in 1932, after he denounced his father to Soviet government authorities and subsequently died at the hands of his family.
 Pavlik Morozov was immortalized in school programs, poetry, music, and in film.
Sergei Mikhailovich Eisenstein (Russian: Сергей Михайлович Эйзенштейн ; ] ; 22 January [O.S. 10 January] 1898 11 February 1948) was a Soviet film director and film theorist, a pioneer in the theory and practice of montage.
 He is noted in particular for his silent films "Strike" (1925), "Battleship Potemkin" (1925) and "" (1928), as well as the historical epics "Alexander Nevsky" (1938) and "Ivan the Terrible" (1944, 1958).
Calcutta Film Society was India’s second film society in the city of Kolkata (then Calcutta), West Bengal, India.
 It was founded in 1947, just after independence, by Satyajit Ray, Chidananda Dasgupta, RP Gupta, Bansi Chandragupta and others.
 The 1925 silent film directed by Sergei Eisenstein, "The Battleship Potemkin" was the first film screened at the film society, which over the years developed the reputation of having the "most cine-literate audiences in the country".
Scapa Flow is a 1930 German drama film directed by Leo Lasko and starring Otto Gebühr, Claire Rommer and Claus Clausen.
 It is set around the Wilhelmshaven Mutiny and the Scuttling of the German fleet in Scapa Flow at the close of the First World War.
 In Weimar Germany the scuttling of the fleet in defiance of the victorious Allies had come to be seen as a popular patriotic act.
 The inclusion of the Mutiny, however, was more controversial as it highlighted the political divisions which continued to exist.
 The film was praised by the right wing press, and comparisons were made to the Russian film "Battleship Potemkin".
 The film was partly inspired by the 1918 play "Seeschalt" by Reinhardt Goering.
Battleship Potemkin is a 2005 album of electronic and orchestral music written by Neil Tennant and Chris Lowe of Pet Shop Boys, to accompany the 1925 silent film "Battleship Potemkin" by Sergei Eisenstein, is performed by Tennant, Lowe and the Dresdner Sinfoniker, conducted by Jonathan Stockhammer, with orchestrations by Torsten Rasch.
 The album was released under the name Tennant/Lowe, as Tennant and Lowe are the composers.
 The album is produced by the Pet Shop Boys and Sven Helbig.
Enno Patalas (born 15 October 1929 in Quakenbrück, Germany) is a German film historian, collector, and expert film preservationist.
 A former head of the Munich Film Museum, his restorations include silent films such as "Metropolis", "M – Eine Stadt sucht einen Mörder" and "Die Nibelungen", all directed by Fritz Lang.
 Patalas also restored the film "The Battleship Potemkin" for viewing at the Berlin Film Festival in 2005.
Edmund Meisel (14 August 1894 – 14 November 1930) was an Austrian-born composer.
 He wrote the score to Walter Ruttmann's "" (1927), "The Battleship Potemkin" (1925), and other films of Sergei Eisenstein.
 Meisel was one of the more important and pioneering figures in film music.
 Much of his work and the evidence of his significance was lost for more than fifty years.
Strike (Russian: Стачка , translit.
 "Stachka") is a 1925 silent film made in the Soviet Union by Sergei Eisenstein.
 It was Eisenstein's first full-length feature film, and he would go on to make "The Battleship Potemkin" later that year.
 It was acted by the Proletcult Theatre, and composed of six parts.
 It was in turn, intended to be one part of a seven-part series, entitled "Towards Dictatorship" (of the proletariat), that was left unfinished.
 Eisenstein's influential essay, "Montage of Attractions" was written between "Strike's" production and premiere.
The Russian battleship "Potemkin" (Russian: Князь Потёмкин Таврический, "Kniaz Potyomkin Tavricheskiy" , "Prince Potemkin of Taurida") was a pre-dreadnought battleship built for the Imperial Russian Navy's Black Sea Fleet.
 It became famous when the crew rebelled against the officers in June 1905 (during that year's revolution), which is now viewed as a first step towards the Russian Revolution of 1917.
 The mutiny later formed the basis of Sergei Eisenstein's 1925 silent film "The Battleship Potemkin".