What major life event affects the protagonist in 'The Magic Mountain'?

In 'The Magic Mountain' by Thomas Mann, the protagonist, Hans Castorp, is profoundly affected by contracting tuberculosis. This illness leads him to spend time at a sanatorium in the Swiss Alps, which serves as the primary setting for the novel. The experience of being diagnosed with this illness becomes a catalyst for deep introspection and philosophical exploration for Hans. As he interacts with other patients, he is drawn into a world that contrasts sharply with his previous life, allowing him to grapple with themes of time, illness, and the nature of existence. This major life event shapes his character development and the narrative arc of the story, making it the most significant influence on his journey throughout the text.

Considering the other choices, they do not reflect the central theme of Hans Castorp's transformative experience in 'The Magic Mountain'. While war, wealth, and travel are important life events, they do not play the pivotal role that the diagnosis of tuberculosis does in driving the protagonist's development and the novel's exploration of existential themes.