Final answer:
The downfall of the Ottoman Empire was chiefly precipitated by World War I, along with challenges such as government corruption and technological lag compared to European powers. World War I marked the empire's disintegration.
Step-by-step explanation:
The event in Europe that ultimately led to the downfall of the Ottoman Empire was World War I. During the 19th century, the Ottoman Empire faced significant challenges, including government corruption, lack of technological development, and weak leadership. European powers took advantage of the weakening empire, leading to the loss of territory and influence.
Various ethnic groups within the Ottoman Empire revolted, as new nation-states emerged in Europe. The empire tried to modernize but fell behind European neighbors and eventually met its end during World War I, marked by the disintegration of its territories and the loss of power.
Additionally, the Industrial Revolution created a significant divide between Western Europe/America and the rest of the world, as Western powers advanced technologically and economically. This compounded the difficulties faced by non-industrialized empires, like the Ottoman Empire, in maintaining power and influence. Overall, the Ottoman Empire's struggle to keep pace with European military advancement and the pressures from internal and external conflicts culminated in its collapse during World War I.