List of military disasters

A military disaster is when one side in a battle or war is unexpectedly and soundly defeated, and often changes the course of history.

A military disaster can range from a strong army losing a major battle against a clearly inferior force, to an army being surprised and defeated by a clearly superior force, to a seemingly evenly matched conflict with an extremely one sided result. A military disaster could be due to bad planning, bad execution, bad weather, general lack of skill or ability, the failure of a new piece of military technology, a major blunder, a brilliant move on the part of the enemy, or simply the unexpected presence of an overwhelming enemy force.

Ancient era

The Battle of Salamis in 480 BC where a huge Persian fleet is defeated by a united Greek force.
The Athenian expedition to Syracuse in 415 BC.
The Battle of Cannae in 216 BC, where Hannibal destroyed the sixteen Roman and Allied legions, led by Lucius Aemilius Paullus and Gaius Terentius Varro. In all, perhaps more than 80% of the entire Roman army was dead or captured (including Paullus himself).
The Battle of Carrhae when Crassus with 40,000 soldiers marched into Parthia expecting to be victorius, chose to march a direct route through the desert instead of the mountains of the north, and was entirely anniliated by 9,000 Parthian soldiers
The Battle of Teutoburg Forest, where German warriors destroyed three Roman legions
The Battle of Watling Street in 60 or 61 AD, where 10,000 Romans, lead by Gaius Suetonius Paulinus, defeated 230,000 Britons, led by Boudica, inflicting 80,000 casualties, and suffering only 400 of their own.
The Battle of Adrianople, in which the emperor Valens was killed while Gothic heavy cavalry ambushed and decimated his Roman heavy infantry.
The Battle of Guandu, which the more powerful Yuan Shao army failed to guard its supplies, and was defeated soundly by Cao Cao in 200 AD.
The Battle of Red Cliffs (also known as the Battle of Chibi), where Liu Bei's advisor Zhuge Liang and Sun Quan's advisor Zhou Yu utterly destroyed Cao Cao's much-larger navy with fire in 208 AD.

Medieval era

The Battle of Yarmuk in 636. The Monophysite Ghassanid contingents in the Byzantine army, brutally persecuted by the Orthodox authorities, defected en masse to the Muslim side thus guaranteeing a Muslim victory.
The Battle of al-Qādisiyyah in 636 - The Arab Muslim army decisively defeated the larger Sassanid Persian army resulting in the Islamic conquest of Persia.
The Battle of Acheloos in 927. An enormous 110,000 Byzantine army was tactically outwitted by a smaller Bulgarian force, causing the death of 90,000 soldiers, 70,000 of whom were Byzantines in one of the bloodiest battles in the Middle Ages. The bones of tens of thousands perished could be seen on the battlefield 75 years later.
The Battle of Hastings in 1066. The Anglo-Saxon King Harold is slain in battle with the Normans led by William the Conqueror, resulting in the Norman Conquest of England.
The Battle of Manzikert in 1071. The Byzantine Empire suffers a humiliating defeat at the hands of the Seljuks, resulting in the capture of Emperor Romanos IV.
The Battle of Hattin in 1187, where overconfident Crusader forces from Jerusalem became trapped in a waterless desert area, and thus became easy prey for the Saracen forces of Salah-ud-din (Saladin)
The Battle of Stirling Bridge in 1297. English Earl John de Warenne's well-equipped army were trapped on a narrow bridge by William Wallace's 15,000 unarmored, lightly-armed Scots, bearing the traditional long spears of lowland Scotland. The bridge had been chosen as the point of engagement by Warenne, even though the river could easily have been forded just a few miles upstream.
The Battle of Agincourt in 1415 - A large force of French knights were mown down by English longbowmen.

16th century

The Battle of Flodden Field - A Scottish invasion of England is defeated, resulting in the death of the King James IV of Scotland
The First battle of Panipat - Babur sacked Delhi and defeated Ibrahim Lodhi.
The Battle of Lepanto in 1571. The Holy League's fleet defeated the Ottoman fleet in one of the largest naval battles of human history. The Ottomans lost 240 ships (out of about 300), while the League lost 12 of their 210 ships.
The Spanish Armada in 1588. An English fleet sends fire ships into the Spanish invasion fleet destroying some and scattering the rest effectively ending the invasion threat. The Armada would later run into storms and almost half the ships never returned to Spain, as well as more than half the troops.
The Battle of the Yellow Ford in 1598. An English force of 4000 is ambushed by Irish defenders under Hugh O'Neill and defeated. This temporarily put Ireland out of English control, allowing the rebellion to spread throughout Ireland.

18th century

Charles XII of Sweden's disastrous wintertime march on Moscow during the Great Northern War marked the beginning of the end of the Swedish Empire.

1761 Panipat's third war was the most disatraous for Marathas.

19th century

The Battle of Bladensburg. War of 1812, the rout of American forces in 1814 by a smaller force of raiding British regulars and Marines under General Robert Ross, which led to the British Burning of Washington. Described in an 1816 American poem as the Bladensburg Races after American troops ran through the streets of Washington in disarray. Ross was later killed by American soldiers on campaign during the Battle of North Point but was subsequently honoured posthumously as Ross of Bladensburg. His US opposite, General William H. Winder, was later court-martialled but cleared of blame.
The Charge of the Light Brigade. A British officer misinterpreted an order and led a suicidal charge against the Russian guns. ("Not tho' the soldier knew, someone had blunder'd" — Tennyson)
Battle of the Little Bighorn. General George Custer attacks a superior force of armed Native American warriors, gets himself and his entire command killed, the only survivor being a lone horse.
Battle of Isandlwana. A Zulu impi armed mostly with spears destroys two British battalions armed with rifles in a Pyrrhic victory.
Napoleon's Invasion of Russia in the summer and winter of 1812 where Napoleon lost almost all of his troops; it was the turning point of the Napoleonic wars.
William Elphinstone's disastrous retreat in 1842 during the First Anglo-Afghan War led to the loss of almost his entire command.
Both the Battle of Fredericksburg and the Battle of Cold Harbor become horrible one-sided battles in which Union advances on entrenched Confederate units result in horrendous casualties during the American Civil War.
Pickett's Charge by the Confederates in the Battle of Gettysburg was easily repulsed and, along with the cost of the previous two days of the battle, permanently crippled the Army of Northern Virginia.
HMS Victoria collided with HMS Camperdown and was sunk with the loss of 358 lives after the fleet commander George Tryon ordered a sudden turn during maneuvres in 1893.
The Battle of Adwa fought between the Italians and Ethiopians in 1896. The Italians were completely defeated and the battle confirmed the independence of Ethiopia.

20th century

The Battle of Tsushima – the Russian Baltic fleet was sent halfway around the world in a suicidal attack on the Japanese in the Tsushima Straits in 1905.
The Battle of Gallipoli in 1915 and early 1916. A combined British, Commonwealth and French attempt to capture Istanbul fails completely at the Gallipoli peninsula.
The Battle of the Somme - an attempt by Allied forces to break the German line during WWI, remembered most for the incredibly high casualties suffered by the British Army. Over 19,000 British soldiers were killed on the first day of the battle, due in part to ineffective artillery preparation of the objective and a gross underestimation of German fortifications.
The Halifax Explosion - A French ship laden with explosives collided with the Norwegian ship Imo, causing massive explosions resulting in a tsunami which devastated the city of Halifax (Canada)
The Battle of Annual in 1921. A 20,000-man Spanish-Moroccan force in the Rif was annihilated by Abd el Krim's much-smaller rebel force, initiating the Rif War.
The Maginot line - although from a strictly technical viewpoint the line itself functioned as designed, it was emblematic of a deeply flawed defensive strategy.
The Battle of France in 1940 - the French Army moved to meet the Germans inside Belgium, believing the Maginot Line would force the Germans to rerun the Schlieffen Plan, but was cutoff by a German advance through the Ardennes, which the French had believed was impassable for tanks. Unlike World War 1 when trench warfare caused Paris to stay French for 4 years, the entire Battle for France was over in 2 months.
Operation Compass in North Africa during winter 1940/41. The Italian army built their forts too far apart so they were not mutually supporting, and lacked tanks or other mobile forces. A British force of 35,000 men was able to rout the Italian army of 150,000, forcing them back 800 km and capturing around 3 times their own number for almost no losses.
Operation Typhoon, the failed German drive towards Moscow in 1941 was exacerbated by the German decision to not bring along any winter clothing and vehicle antifreeze.
The Attack on Pearl Harbor seemed a serious victory against the US Pacific Fleet for the Empire of Japan on December 7, 1941. However, the attack came to be a long term strategic blunder that inflicted little significant lasting harm on American forces while provoking an overwhelming response that led to Japan's crushing defeat.
The fall of Singapore (believed to be an impregnable fortress) in February 1942 to two Japanese divisions was the largest surrender of British-led troops in history and destroyed the linchpin of the American-British-Dutch-Australian Command. The British Commonwealth overestimated the size of the Japanese invasion force which was 1/3 of the size of the defending force and surrendered.
The naval Battle of Midway. Admiral Yamamoto of the Imperial Japanese Navy attempted to invade the American navy base at Midway Island. US navy intelligence broke his codes and anticipated the attack. The Imperial Japanese Navy lost four fleet carriers in three days partly due to the decision to refuel their aircraft simultaneously on the flight deck, making the fuel hoses and aircraft vulnerable to bombing.
The Allied Dieppe Raid on German-occupied France in 1942 ended with ~60 % of the attacking force being lost in battle without any of the major objectives of the raid achieved.
The Battle of Stalingrad in the winter of 1942/43 was one of the turning points of World War II. The German General Friedrich Paulus failed to keep a mobile strategic reserve and the entire (and formerly invulnerable) 6th Army was surrounded on all sides by a rapid Russian flanking attack. Rubble caused by excessive bombing and artillery by the German troops had left their tanks unable to effectively enter the city. The German troops in Stalingrad surrendered even though Hitler had promised that they would never leave the city.
Operation Bagration (1944) the Soviet summer offensive sliced through the Germans and reached Poland within two weeks, the offensive also destroyed army group centre, the backbone of German forces in the east.
Operation Market Garden A British plan to encircle the Ruhr Area and end the war by Christmas. The plan failed due to the entire army having to advance along a single road, making them vulnerable to attack on both sides, costing over 15,000-17,000 Allied casualties.
The Battle of Dien Bien Phu, which forced the French to withdraw from northern Vietnam in 1954.
The Bay of Pigs Invasion, a United States-backed 1961 attempt to overthrow Cuban President Fidel Castro with 1,500 Cuban exiles. Not only were the exiles heavily outnumbered when they reached the bay, but the US-promised air support never came to aid the exiles.
The Six-Day War, in response to Arab threats of invasion, Israel launched surprise air attacks which almost completely destroyed the Air Forces of Egypt, Jordan, and Syria, then launched a series of ground, air, and naval attacks which saw the capture of the Sinai from Egypt, the [[West Bank] from Jordan, and the Golan Heights from Syria, and heavy Arab losses in personnel and material.
USS Liberty incident, the United States Navy Technical Research Ship USS Liberty was attacked by Israeli jets and torpedo boats on June 8, 1967, after the ship was supposedly mistaken for an Egyptian vessel. A total of 34 sailors were killed and 171 wounded, and the ship was heavily damaged.
1967 USS Forrestal fire – a disastrous fire broke out aboard the aircraft carrier during the Vietnam War, killing 134, injuring 161, destroying 21 aircraft and costing the Navy $72 million. John McCain was a US Navy pilot aboard the aircraft carrier at the time and his aircraft was one of the first involved in the fire.
The Battle of Longewala, a battle of the Indo-Pakistani War of 1971 in which an Indian force of 120 infantry men armed with small arms repelled a Pakistani force comprising of 2800 soldiers and 65 tanks.

21st century

Operation Eagle Claw, a US attempt to rescue hostages in Iran. This operation was marked by a series of mechanical and communication failures that lead to the deaths of 8 American servicemen, and failed to rescue the hostages.
The 2008 attack on Omdurman and Khartoum was an attempt by the Justice and Equality Movement (JEM), a Darfur-based rebel group, to capture the Sudanese cities of Khartoum (the capital) and Omdurman (the largest city). The attacks were repulsed by Sudanese military and police forces. The bodies of 90 JEM rebels were found, with dozens more scattered outside the city, and two thirds of their 180 vehicles were destroyed. Scores of JEM rebels were captured, and many were executed.^[1]^[2]