How did Carl Fisher make his money?

Can you elaborate on the sources of Carl Fisher's wealth? Was his fortune primarily derived from his involvement in the automotive industry, specifically his role in the development of the Indianapolis Motor Speedway? Or did he also diversify his investments into other areas, such as real estate or technology? How did his business acumen and strategic vision contribute to his success? Additionally, were there any key partnerships or collaborations that played a significant role in his financial growth?