WORLD WAR I

ASSASSINATION OF ARCHDUKE FRANZ FERDINAND

Jun 28, 1914

Heir to the Austro-Hungarian throne is assassinated in Sarajevo, igniting tensions across Europe.

AUSTRIA-HUNGARY DECLARES WAR ON SERBIA

Jul 28, 1914

This declaration triggers a chain of alliances and declarations of war.

EUROPE MOBILIZES FOR WAR

Aug 1, 1914

Germany declares war on Russia (August 1) and France (August 3). Britain declares war on Germany on August 4 after Germany invades Belgium.

FIRST BATTLE OF THE MARNE

Sep 6, 1914

Allied forces halt the German advance into France, leading to a stalemate and the beginning of trench warfare on the Western Front.

SECOND BATTLE OF YPRES

Apr 22, 1915

Germany uses poison gas (chlorine) for the first time on a large scale, marking the beginning of chemical warfare.

BATTLE OF VERDUN

Feb 21, 1916

One of the longest and costliest battles of the war, with massive casualties on both sides.

BATTLE OF SOMME

Jul 1, 1916

British and French forces launch an offensive against Germany; notable for the high casualties and the first use of tanks by the British.

UNITED STATES ENTERS THE WAR

Apr 6, 1917

The U.S. declares war on Germany following unrestricted submarine warfare and the Zimmermann Telegram.

BATTLE OF PASSCHENDAELE

Jul 31, 1917

Known for the horrendous mud and high casualty rates, marking little strategic gain for the Allies.

GERMAN SPRING OFFENSIVE

Mar 21, 1918

Germany launches a series of major attacks on the Western Front, initially making gains but ultimately failing.

SECOND BATTLE OF THE MARNE

Jul 15, 1918

Allied forces counterattack successfully, marking the beginning of the German retreat.

ARMISTICE

Nov 11, 1918

An armistice is signed in Compiègne, France, ending fighting on the Western Front at 11:00 a.m. This day is commemorated as Armistice Day or Remembrance Day.

TREATY OF VERSAILLES

Jun 28, 1919

The main peace treaty that officially ends the state of war between Germany and the Allied Powers, placing heavy reparations and territorial losses on Germany.

TREATY OF SAINT-GERMAIN

Jun 28, 1919

The treaty marked the official end of the First World War for Austria and for the majority of the states and kingdoms comprising the former Austro-Hungarian Empire, with the exception of Hungary, who would sign their own peace treaty, the Treaty of Trianon, on 4 June 1920.

TREATY OF NEUILLY

Nov 27, 1919

Bulgaria had to cede the rich wheat‐growing area of southern Dobrudja to Romania and western Thrace to Greece, thus losing direct access to the Mediterranean.