Gallipoli
The Gallipoli campaign of 1915-16 is still infamous as arguably the most ill-conceived, badly led and pointless campaign of the entire First World War. The Allied commanders were ignorant of the terrain, and seriously underestimated the Turkish army which had been bolstered by their German allies. Thus the Allies found their their troops hopelessly entrenched on the hillsides for long agonising months, through the burning summer and bitter winter, in appalling conditions.