It depends on which war you are asking about. In World War 2 it was at Dunkirk in May 1940.
At port taco town
The battle of Adrianople was one of Romans worst defeats.
The British military commander who sustained one of the worst defeats in English history in 1755 in western Pennsylvania was General Edward Braddock. He led an expedition against French forces and their Native American allies during the early stages of the French and Indian War. However, Braddock's forces were ambushed and suffered a decisive defeat in the Battle of the Monongahela.
The Battle of the Nations which was one of Napoleon's major defeats. It was the largest European battle prior to World War One.
Barbary_CoastWar one of the best defeats of his own
in 57 B.C. the Roman army chased the Parthinians (or Persians) into Iran, who then handed the Romans one of the worst defeats of the Empire, killing 20,000 soldiers and taking another 10,000 prisoner.
Alfred Hitchcock
My brother!! David Jacobs is also a British Disc-jockey. According to himself, the World's Worst one.
War.
The disaster at Teutoberg was Rome's greatest defeat.The disaster at Teutoberg was Rome's greatest defeat.The disaster at Teutoberg was Rome's greatest defeat.The disaster at Teutoberg was Rome's greatest defeat.The disaster at Teutoberg was Rome's greatest defeat.The disaster at Teutoberg was Rome's greatest defeat.The disaster at Teutoberg was Rome's greatest defeat.The disaster at Teutoberg was Rome's greatest defeat.The disaster at Teutoberg was Rome's greatest defeat.
In the summer of 1940, 338000 British and French troops were evacuated from the beaches at Dunkirk in Northern France after having been thoroughly beaten by superior German Forces. It was one of the worst defeats the British Army has ever suffered but propaganda at the time made it sound like a victory. There is no doubt that the logistics of the evacuation were nothing short of a miracle.
Russia had problems fighting on the eastern front during WW1, because Russia was poorly equipped to fight a modern war. Russians suffered one of the worst defeats of the war, causing them to retreat.