It is a common trope, in the software world and elsewhere, that failure can breed success. This is evident at the micro scale – failing code/tests are an inevitable starting condition for working code and passing tests.
At the more macro scale, there is an entire conference on the theme of startup failure and lessons learned from that failure. While no one should glorify failure, you want this kind of culture – having some acceptance of failure reduces the social risk of starting a new venture.
Some acceptance of failure is not unheard of in the military world either. I actually chose my first screen name based on a major event on this theme.
If a bigger and more comprehensive failure increases learning experience, then the Gallipoli campaign of 1915 was a serious education for the Allies. For them, everything went wrong.
First the backstory:
The Gallipoli Campaign…took place on the Gallipoli peninsula (Gelibolu in modern Turkey) in the Ottoman Empire between 25 April 1915 and 9 January 1916, during World War I. […] an amphibious landing was undertaken on the Gallipoli peninsula, to capture the Ottoman capital of Constantinople (Istanbul). After eight months the land campaign also failed with many casualties on both sides, and the invasion force was withdrawn to Egypt.
The Many Problems Faced by the Anzacs
They faced a motivated, dynamic, and prepared opposition lead by the founding father of modern Turkey.
Exceedingly poor inter-branch communication/cooperation. There was no unified command for the operation – the navy was commanded independently and failed to clear the Dardanelles straits.
Incompetent logistician work. Many ships were not combat loaded and needed to stop in Alexandria to be reorganized, delaying for a month.
Contemporary military technology heavily favored the defensive and tactics to mitigate massed defensive firepower were primitive
Poor training and preparation. Both forces acted with bravery and stoicism under incredible hardships, but both received limited training in the run-up to the battle.
“…it took place in circumstances in which nearly everything was experimental: in the use of submarines and aircraft, in the trial of modern naval guns agains artillery on the shore…the use of radio…land mines” (Alan Moorehead, Gallipoli)
Gallipoli was a fiasco. A commission was set up to examine the incident and
…concluded that the expedition was poorly planned and executed and that difficulties had been underestimated, problems which were exacerbated by supply shortages and by personality clashes and procrastination at high levels.
Much of the blame fell on this guy:
Chief Lord of the Admiralty, Winston Churchill. He was demoted and resigned. But as it turns out he wasn’t done with politics.
Gallipoli is textbook example of unsuccessful modern amphibious attacks.
the campaign “became a focal point for the study of amphibious warfare” in the United Kingdom and United States because it involved “all four types of amphibious operations: the raid, demonstration, assault and withdrawal”.
Unified command. Understanding of the terrain. The element of surprise. Rapid expansion from the beachhead. Overwhelming fire suppression. Proper logistical and training preparation. Lessons hard learned.
This information directly informed planners and the strategic thinking of Allied leaders when formulating the Normandy invasion. From the BBC:
[The planners] had grasped the vital necessity for an adequate period of planning for all three services – the army, navy and air force.
Meanwhile the slaughter on the Gallipoli beaches had taught the planners the necessity of smothering the immediate beach areas with massed fire from rocket ships and mortars to neutralise German defensive positions.
Churchill certainly never forgot Gallipoli. In the 1920s, he published The World Crisis, which went into great detail – step by step – into the political and strategic background of the campaign (Moorehead). And later he was instrumental in making the Normandy landings possible and successful.
 The commander of Ottoman forces was one Mustafa Kemal, now more commonly known as Atatürk or “Father of Turks” and went on to found the modern nation of Turkey. Reacting quickly to the Anzac landings, he launched a vicious counterattack which seized the high ground and essentially doomed the invasion.