How will the youngest day be

Judgment Day

Examples:

The reformers lived in anticipation of Judgment Day. [Neue Zürcher Zeitung, 09.08.2017]

Finally, in Islam, belief in Judgment Day is central to religion; The Koran depicts the day of God's judgment in numerous verses. [Süddeutsche Zeitung, July 2nd, 2016]

[...] "Don't play with the lives of your brothers and sisters, don't sell your soul to the devil ... Because when Judgment Day has come, you have to justify yourself to God." [Der Standard, December 20, 2014]

The Christian medieval worldview was strongly dominated by eschatological [eschatological] ideas such as those found in the Revelation (Apocalypse) of John. According to the popular belief, creation will last 6,000 years until the world ends and Christ returns at the Last Judgment (Parousia). The dead, too, were believed to be resurrected on that last day and appear before the judgment seat of Christ. [Zeit Geschichte, 02/16/2010]

This voice screamed that the end of the world and Judgment Day had dawned. [Captain, Gerhart: The fool in Christo Emanuel Quint, Berlin: Aufbau-Verl. 1962 [1910], p. 259]

exaggerated, jokingly indefinite point in time in the future that may never happen

Synonymous with the Last Judgment (●), never a day

Collocations:

in prepositional group / object: until Judgment Day

Examples:

Behind the hall, not visible from the street, a dozen wrecks are waiting for Judgment Day, when Jim will decide what to do with the junk truck. [Welt am Sonntag, 05.08.2012]

The fact is that the black swan fell in love with a pedal boat that has a plastic gooseneck and is therefore completely unable to relate. So he can paddle around his playmate until Judgment Day (= for all eternity), then nothing will happen anymore. [Süddeutsche Zeitung, 16.09.2006]

One day, that is certain, the last cinema will say goodbye to its last visitor, but luckily nobody knows when this youngest day will begin. [Süddeutsche Zeitung, April 14, 2007] unusual. Spelling

[...] your laughter, I could hear that until the last day (= forever). [Picture on Sunday, October 4th, 2015] unusual. Spelling