Historical clue formulations

• Conflict sparked by an archduke's assassination: Abbr. — 2026-07-05
• Historical event that acquired its name almost two decades after it ended, in brief — 2025-08-09
• Era in which daylight saving was introduced as a way to conserve energy, in brief — 2025-07-24
• Conflict of 1914-18, in brief — 2023-11-20
• Setting for the film "1917," familiarly — 2023-11-18
• "All Quiet on the Western Front" setting, for short — 2023-08-13
• Backdrop for the 2019 film "1917": Abbr. — 2023-07-07
• Setting of the Robert Graves memoir "Good-bye to All That," in brief — 2022-01-01
• Historical event given its current name in 1939: Abbr. — 2021-12-23
• Conflict in 2017's "Wonder Woman," in brief — 2021-10-17
• Conflict that ended at 11:00 on 11/11 — 2021-03-31
• Conflict in 2017's "Wonder Woman," in brief — 2021-02-08
• It ended on Nov. 11, 1918 — 2020-09-06
• Conflict during which the Lusitania was sunk: Abbr. — 2020-08-09
• "A Farewell to Arms" subj. — 2019-02-21
• 1914-18 conflict, for short — 2019-02-05
• Teens fight, for short — 2018-04-06
• The U.S. joined it in 1917: Abbr. — 2017-10-29
• "A Farewell to Arms" setting, briefly — 2017-08-24
• Chapter in early 20th-century history: Abbr. — 2017-01-22
• "Over There" subj. — 2015-01-25
• 1910s conflict: Abbr. — 2014-09-08
• What the U.S. joined in Apr. 1917 — 2013-03-23
• Conflict for which "Over There" was written: Abbr. — 2013-02-19
• A.E.F.'s conflict — 2009-10-21
• The 1919 Treaty of Versailles concluded it: Abbr. — 2008-01-28
• It ended on Nov. 11 — 2006-04-05
• La Belle Époque ender: Abbr. — 2005-09-11
• It ended at 11:00 on 11/11 — 2005-07-26
• Conflict that ended at 11:00 on 11/11 — 2001-07-08
• When tank warfare began: Abbr. — 1999-05-21
• Old Eur. conflict — 1999-01-10
• A.E.F. conflict — 1996-09-30
• Teens conflict: Abbr. — 1995-03-26