You can find out all about the First World War by visiting our First World War Galleries. Discover over 1,300 objects from IWM’s collections including weapons, uniforms, diaries, keepsakes, film and art, uncover the stories of thousands who gave their lives in the war to end all wars. Learn more and plan your visit.
1. First Battle of the Marne
At the start of the First World War, Germany hoped to avoid fighting on two fronts by knocking out France before turning to Russia, France’s ally. The initial German offensive had some early success, but there were not enough reinforcements immediately available to sustain momentum. The French and British launched a counter-offensive at the Marne (6-10 September 1914) and after several days of bitter fighting the Germans retreated.
Germany’s failure to defeat the French and the British at the Marne also had important strategic implications. The Russians had mobilised more quickly than the Germans had anticipated and launched their first offensive within two weeks of the war’s outbreak. The Battle of Tannenberg in August 1914 ended in German victory, but the combination of German victory in the east and defeat in the west meant the war would not be quick, but protracted and extended across several fronts.
The Battle of the Marne also marked the end of mobile warfare on the Western Front. Following their retreat, the Germans re-engaged Allied forces on the Aisne, where fighting began to stagnate into trench warfare.
The opening months of the war caused profound shock due to the huge casualties caused by modern weapons. Losses on all fronts for the year 1914 topped five million, with a million men killed. This was a scale of violence unknown in any previous war. The terrible casualties sustained in open warfare meant that soldiers on all fronts had begun to protect themselves by digging trenches, which would dominate the Western Front until 1918.
The Gallipoli campaign (25 April 1915 - 9 January 1916) was the land-based element of a strategy intended to allow Allied ships to pass through the Dardanelles, capture Constantinople (now Istanbul) and ultimately knock Ottoman Turkey out of the war. But Allied plans were based on the mistaken belief that the Ottomans could be easily overcome.
At dawn on 25 April 1915, Allied troops landed on the Gallipoli peninsula in Ottoman Turkey. General Sir Ian Hamilton decided to make two landings, placing the British 29th Division at Cape Helles and the Australian and New Zealand Army Corps (ANZAC) north of Gaba Tepe in an area later dubbed Anzac Cove. Both landings were quickly contained by determined Ottoman troops and neither the British nor the Anzacs were able to advance.
Trench warfare quickly took hold, mirroring the fighting of the Western Front. Casualties mounted heavily and in the summer heat conditions rapidly deteriorated. Sickness was rampant, food quickly became inedible and there were vast swarms of black corpse flies. In August a new assault was launched north of Anzac Cove. This attack, along with a fresh landing at Suvla Bay, quickly failed and stalemate returned.
In December, it was decided to evacuate – first Anzac and Suvla, and then Helles in January 1916. Gallipoli became a defining moment in the history of both Australia and New Zealand, revealing characteristics that both countries have used to define their soldiers: endurance, determination, initiative and 'mateship'. For the Ottomans, it was a brief respite in the decline of their empire. But through the emergence of Mustafa Kemal (later known as Atatürk) as one of the campaign's leading figures, it also led to the foundation of modern Turkey.
The Battle of Jutland (31 May - 1 June 1916) was the largest naval battle of the First World War. It was the only time that the British and German fleets of 'dreadnought' battleships actually came to blows.
The German High Seas Fleet hoped to weaken the Royal Navy by launching an ambush on the British Grand Fleet in the North Sea. German Admiral Reinhard Scheer planned to lure out both Admiral Sir David Beatty’s Battlecruiser Force and Admiral Sir John Jellicoe's Grand Fleet. Scheer hoped to destroy Beatty’s force before Jellicoe’s arrived, but the British were warned by their codebreakers and put both forces to sea early.
Jutland was a confused and bloody action involving 250 ships and around 100,000 men. Initial encounters between Beatty’s force and the High Seas Fleet resulted in the loss of several ships. The Germans damaged Beatty’s flagship, HMS Lion, and sank HMS Indefatigable and HMS Queen Mary, both of which blew up when German shells penetrated their ammunition magazines.
Beatty withdrew until Jellicoe arrived with the main fleet. The Germans, now outgunned, turned for home. Although it failed to achieve the decisive victory each side hoped for, the battle confirmed British naval dominance and secured its control of shipping lanes, allowing Britain to implement the blockade that would contribute to German defeat in 1918.
The British lost 14 ships and over 6,000 men, but were ready for action again the next day. The Germans, who had lost 11 ships and over 2,500 men, avoided complete destruction but never again seriously challenged British control of the North Sea.
4. Battle of Verdun
The Battle of Verdun (21 February - 18 December 1916) was the longest battle of the First World War. It was also one of the costliest. It began in February 1916 with a German attack on the fortified French town of Verdun, where bitter fighting would continue for most of the year.
The ten-hour opening bombardment saw an unprecedented concentration of firepower and although the French were forced back they did not break. In the summer, the Germans were forced to reduce their strength at Verdun after the British and Russians launched their own offensives elsewhere.
The French retook lost ground in the autumn and through careful management of their army, efficient logistics and the resilience of the troops fighting for their homeland, the French secured a defensive victory before the year’s end.
The Germans had lost over 430,000 men killed or wounded and the French approximately 550,000. The trauma of this loss not only affected French political and military decision-making during and after the war, it had a lasting effect on French national consciousness.
Verdun also had serious strategic implications for the rest of the war. The Allies had planned to defeat Germany through a series of large co-ordinated offensives, but the German attack at Verdun drastically reduced the number of French troops available. Britain and its Empire would have to lead the 'Big Push' on the Western Front.
5. Battle of the Somme
The Battle of the Somme (1 July - 18 November 1916) was a joint operation between British and French forces intended to achieve a decisive victory over the Germans on the Western Front. For many in Britain, the resulting battle remains the most painful and infamous episode of the First World War.
In December 1915, Allied commanders had met to discuss strategies for the upcoming year and agreed to launch a joint French and British attack in the region of the River Somme in the summer of 1916. Intense German pressure on the French at Verdun throughout 1916 made action on the Somme increasingly urgent and meant the British would take on the main role in the offensive.
They were faced with German defences that had been carefully laid out over many months. Despite a seven-day bombardment prior to the attack on 1 July, the British did not achieve the quick breakthrough their military leadership had planned for and the Somme became a deadlocked battle of attrition.
Over the next 141 days, the British advanced a maximum of seven miles. More than one million men from all sides were killed, wounded or captured. British casualties on the first day – numbering over 57,000, of which 19,240 were killed – make it the bloodiest day in British military history.
The Somme, like Verdun for the French, has a prominent place in British history and popular memory and has come to represent the loss and apparent futility of the war. But the Allied offensive on the Somme was a strategic necessity fought to meet the needs of an international alliance. British commanders learned difficult but important lessons on the Somme that would contribute to eventual Allied victory in 1918.
6. Brusilov Offensive
The Russian Army had suffered a series of crushing defeats in the first year of the war, but the Brusilov Offensive (4 June - 20 September 1916) would be the most successful Russian offensive – and one of the most successful breakthrough operations – of the First World War.
Named after the Russian commander Aleksei Brusilov who led it, the offensive used tactics that were to also prove successful on the Western Front. Brusilov used a short, sharp artillery bombardment and shock troops to exploit weak points, helping to return an element of surprise to the attack.
The offensive coincided with the British attack on the Somme and was part of the effort to relieve pressure not only on the French at Verdun, but on the Western Front as a whole. The Russian attack also drew Austro-Hungarian forces away from the Italian Front and put increased pressure on the already strained and increasingly demoralised Austro-Hungarian Army.
Germany was forced to redirect troops to the Eastern Front in support of its ally. This was part of an emerging pattern of Austria-Hungary’s growing dependence on Germany, which in turn would create a strain on German resources.
The Russians were never able to duplicate Brusilov's success. It was their last major offensive of the war and led to an overall weakening – both militarily and politically – of both Russia and Austria-Hungary. The war stoked political and social unrest, leading to revolution and eventually the total collapse of the Russian Army.
7. Third Ypres Campaign
The Third Battle of Ypres (31 July - 10 November 1917) has come to symbolise the horrors associated with the war on the Western Front. It is frequently known by the name of the village where it culminated – Passchendaele.
The area surrounding the Belgian town of Ypres was a key battleground throughout the war. By 1917 British forces were suffering steady casualties there, holding a salient surrounded by higher ground. Sir Douglas Haig planned to break out of this poor position and, by capturing an important rail junction a few miles to the east, to undermine the whole German position in Flanders. If this succeeded he hoped to threaten the German submarine base at Bruges as the German U-boat campaign was threatening Britain with defeat.
A preliminary operation to seize the Messines Ridge was a dramatic success, but the Germans had reinforced their position by the time the main battle was launched on 31 July. Initial attacks failed due to over-ambitious plans and unseasonal rain. The drainage of the low-lying battlefield had been destroyed by the bombardment, creating muddy conditions that made movement difficult.
Drier conditions in September enabled British forces to make better progress during this phase of the offensive. This demoralised the Germans, who did not have an answer to the British 'bite and hold' tactics of taking limited portions of German positions and holding it against counter-attacks that cost the German Army further casualties.
This period encouraged Haig to continue the offensive in October. But the rain returned and conditions once again deteriorated. Although the Canadians finally captured Passchendaele ridge on 10 November, the vital railway still lay five miles away. The offensive was called off. Many soldiers felt utterly demoralised and the government's confidence in Haig hit a low point. Both sides had suffered heavy casualties, but the British Expeditionary Force (BEF) had made no strategic gain.
8. German Spring Offensives
The German Spring Offensives (21 March - 18 July 1918) represented a calculated gamble for Germany in trying to tip the balance on the Western Front once and for all. Operation 'Michael', the first of the offensives, began on the damp and misty morning of 21 March 1918. British and Allied troops were met with a huge concentration of German artillery, gas, smoke and infantry. The German Army achieved unprecedented gains measured in miles rather than yards.
Germany had concentrated all of its resources on the Western Front after the defeat of Russia. Facing them were weary Allied forces that for three years had largely been on the offensive, had not fully organised their defences in depth and were beginning to suffer manpower shortages.
In the face of the onslaught the Allied line bent but did not break. The fighting became uncharacteristically open as isolated pockets of defenders attempted to slow the German advance. Such was the situation that on 11 April, Field Marshal Sir Douglas Haig issued a special order of the day using the phrase 'Backs to the Wall' to sum up the desperate but determined fighting in progress that needed to be maintained.
But whilst the German offensives were tactical successes, they were strategic failures. The advances had no decisive goal other than to punch a hole in the Allied line and primarily target the British. The largest gains took place where the Allies were most willing to give ground. German casualties were high, particularly amongst the best units. The Allies appointed Marshal Ferdinand Foch as Allied Generalissimo to better co-ordinate a united defence. The tide began to turn and by early summer the German offensives ground to a halt.
9. Battle of Amiens
9. Battle of Amiens
The Battle of Amiens (8-11 August 1918) heralded the start of the Hundred Days campaign, a four-month period of Allied success. After surviving the German Spring Offensives, Allied forces launched a counter-punch of their own and from the summer of 1918 onwards, they were constantly on the advance.
Through the harsh experiences of the past the Allies had developed advanced operational methods that best used the materiel power at their disposal. The British Expeditionary Force (BEF) was at the forefront, combining scientific artillery methods and flexible infantry firepower with the use of tanks and aircraft. These combined arms methods were to form a blueprint for the future.
The first Allied counter-attacks began in July and the Battle of Amiens opened on 8 August. Secretive preparations ensured surprise and the BEF made gains of seven miles on that one day – German General Erich Ludendorff described it as the 'black day' of the German Army. But unlike offensives of the past, the Allies now knew when to stop. After four days of fighting at Amiens the battle was halted as its effects diminished, with a fresh offensive launched elsewhere. This set the pattern for success. A series of co-ordinated hammer blows forced increasingly exhausted German forces back.
Allied attacks were flexible, utilising surprise and mobility but also the methodical approach of 1917 when necessary to break German defences. Casualties were still significant, but the gains were decisive. By November the German Army could fight no longer. It had been pushed back to the battlefields of 1914 and was moving in only one direction. The Hundred Days was an impressive feat of arms that led to Allied victory.
10. Battle of Megiddo
The Battle of Megiddo (19-25 September 1918) marked the beginning of the final British-led offensive in the Sinai and Palestine Campaign. It successfully combined cavalry, infantry, artillery, armoured vehicles and aircraft to achieve decisive victory over the Ottoman Turks and their German allies. It was the start of a series of important Allied victories that ultimately led to the collapse of Ottoman Turkish forces and their eventual withdrawal from the war.
On 19 September the Egyptian Expeditionary Force (EEF), under the leadership of British Lieutenant-General Sir Edmund Allenby, launched an offensive against Ottoman forces in northern Palestine and the Jordan Valley. Allenby's plan was to encircle Ottoman forces regrouping in the area around Megiddo and cut off their escape routes. A successful Allied deception campaign had convinced Ottoman forces that an Allied attack would come further east, leaving Ottoman defences in coastal Palestine vulnerable and ultimately outnumbered.
The offensive opened with an intense but brief artillery bombardment. British and Commonwealth forces quickly broke through the battered Ottoman lines with an advance of over 30km on the first day. The Desert Mounted Corps then quickly pushed through gaps in the defences to encircle the Ottoman troops. The Ottoman Eighth and Seventh Armies collapsed under the pressure of the Allied attack, surrendering in the tens of thousands.
Victory at Megiddo opened the way to Damascus, which Australian troops entered on 1 October. In the weeks that followed, the Allies captured other strategically important cities. On 30 October, the Ottoman Empire sought a peace settlement with the Allies and an armistice was signed at Mudros, with hostilities ceasing at 12 noon the following day. This was also after Turkish forces were defeated by Britain and its allies in Mesopotamia.
This article was written by Matt Brosnan, Paul Cornish, Nick Hewitt, Ian Kikuchi, Nigel Steel and Jessica Talarico.