During which historical event did significant Chinese immigration to the U.S. occur?

Significant Chinese immigration to the U.S. occurred during the Gold Rush, which began in 1848. The promise of wealth and opportunity attracted a large number of Chinese immigrants, many of whom were drawn to California in pursuit of gold. This era marked the first major wave of Chinese immigration to the United States, as individuals and families sought to improve their economic circumstances.

During this time, the Chinese faced numerous challenges, including discrimination and violence, yet they played a crucial role in various sectors, especially in mining and later in building the transcontinental railroad. This influx had lasting impacts on both Chinese communities and American society, ultimately leading to cultural exchanges and significant demographic changes.

The other options reflect historical events that did not experience the same level of significant Chinese immigration as the Gold Rush. For example, while World War I involved many immigrants from various countries, it did not significantly increase Chinese immigration. The Great Depression led to a decrease in overall immigration as economic opportunities dwindled. The Spanish-American War, occurring at a different historical context, did not similarly attract large numbers of Chinese immigrants. Therefore, the Gold Rush stands out as the pivotal event associated with significant Chinese immigration to the U.S.