Question: Which monument in Oberndorf bei Salzburg is dedicated to a Christmas carol that Franz Xaver Gruber is best known for composing? 

Context articles: Arts Initiative KNIE
Nicolas Reissig
Silent Night
Richard Wendler
Florian Wenninger
Ludwig Paischer
Franz Xaver Gruber
Oberndorf bei Salzburg
Leopold Kohr
Silent-Night-Chapel

Arts Initiative KNIE was founded as an initiative for contemporary art in 1995 in Oberndorf bei Salzburg.
 It is the origin of the stolperstein project in Braunau am Inn District.
Nicolas Reissig (born 7 April 1989, in Oberndorf bei Salzburg) is an Austrian tennis player.
 Reissig has a career high ATP singles ranking of 344, achieved on 15 July 2013.
 Reissig made his ATP main draw doubles debut at the 2014 MercedesCup partnering Robin Kern, losing in the first round to Mate Pavić and André Sá.
 Reissig has a total of 7 singles titles and 4 doubles titles on the futures circuit.
"Silent Night" (German: "Stille Nacht, heilige Nacht" ) is a popular Christmas carol, composed in 1818 by Franz Xaver Gruber to lyrics by Joseph Mohr in the small town of Oberndorf bei Salzburg, Austria.
 It was declared an intangible cultural heritage by UNESCO in 2011.
 The song has been recorded by a large number of singers from every music genre.
 The version sung by Bing Crosby is the third best-selling single of all-time.
Richard Wendler (22 January 1898, Oberndorf bei Salzburg – 24 August 1972, Prien am Chiemsee) was a high-ranking Nazi official during World War II.
 During the occupation of Poland, he was the Governor of new District Lublin in the General Government, in charge of Lublin concentration camp and the creation of the Częstochowa Ghetto, among others.
 Before his deployment to Poland, he was the mayor of the city Hof between 1933 and 1941 and became an SS-"Gruppenführer" in 1942 during the murderous Operation Reinhard.
 Wendler was "Reichsführer-SS" Heinrich Himmler's brother-in-law; his sister was married to a brother of Himmler.
Florian Wenninger (born 5 July 1978 in Oberndorf bei Salzburg) is an Austrian historian, dedicating himself mainly to the history of totalitarian regimes in the 20th century.
Ludwig Paischer (born 28 November 1981 in Oberndorf bei Salzburg) is an Austrian judoka.
Franz Xaver Gruber (25 November 1787 – 7 June 1863), was an Austrian primary school teacher, church organist and composer in the village of Arnsdorf, who is best known for composing the music to "Stille Nacht" ("Silent Night").
Oberndorf bei Salzburg is a town in the Austrian state of Salzburg, about 17 km (11 mi) north of the City of Salzburg.
 It is situated on the river Salzach in the Flachgau district.
Leopold Kohr (5 October 1909 in Oberndorf bei Salzburg, Austria – 26 February 1994 in Gloucester, England) was an economist, jurist and political scientist known both for his opposition to the "cult of bigness" in social organization and as one of those who inspired the" small is beautiful" movement.
 For almost twenty years, he was Professor of Economics and Public Administration at the University of Puerto Rico.
 He described himself as a "philosophical anarchist."
 His most influential work was "The Breakdown of Nations".
The Silent Night Chapel (Stille-Nacht-Kapelle) is located in the town Oberndorf bei Salzburg in the Austrian province of Salzburg and is a monument to the Christmas carol "Silent Night" and its librettist, Joseph Mohr and composer, Franz Xaver Gruber.
 It stands in place of the former St. Nicholas Church, where on 24 December 1818 the Christmas carol was performed for the first time.