The 20th century was a transformative period for Toronto, marked by both adversity and progress. In 1904, the Great Toronto Fire ravaged the city, destroying over 100 buildings and causing extensive damage, but this setback was just the beginning of the city's resilience. As new waves of immigrants from Europe, including Germans, Italians, Jews, and Russians, arrived in the early 20th century, the city’s population surged. These migrants often lived in overcrowded conditions, particularly in the "Ward" area, but as they prospered, they moved to better housing, fueling the city's expansion.

The 1920s saw Toronto grow in economic importance, though it remained second to Montreal. By 1934, the Toronto Stock Exchange had overtaken Montreal’s, solidifying Toronto's role as the financial capital of Canada. The postwar boom further spurred suburban development, and by 1954, the creation of Metropolitan Toronto consolidated the city and surrounding municipalities into a regional government.

However, disasters continued to strike. In 1954, Hurricane Hazel caused widespread devastation, killing 81 people and leaving thousands homeless. The 1960s and 1970s saw a wave of immigration from countries such as Italy, Portugal, and China, contributing to Toronto's diversity and rapid growth. By the 1980s, Toronto had surpassed Montreal in both population and economic significance, cementing its role as Canada's largest and most influential city.

In 1998, the city underwent a significant transformation with the amalgamation of its six municipalities into the “megacity,” a move that was initially met with public resistance. Toronto continued to grow in the 21st century, becoming North America's fastest-growing city by 2019. The city also faced challenges, including the SARS outbreak in 2003 and the devastating ice storm of 2013, but it continued to thrive.

Toronto's global stature has been bolstered by hosting major events like the 2015 Pan American Games and WorldPride in 2014. The city's resilience, ever-expanding population, and role as an international hub underscore its remarkable evolution from the early days of its settlement to the thriving metropolis it is today.