What powered the greatest consumer boom the world has ever seen?

The discovery of oil

Explanation:

There are numerous theories about the emergence of oil, but the most accepted is that it came from the organic remains of animals and plants deposited at the bottom of lakes and seas undergoing chemical transformations over thousands of years.

The first oil well was discovered in the United States - Pennsylvania - in the year 1859. It was found in a shallow (21m) region. However, it was in 1900 that oil peaked causing the great consumer boom the world has ever seen.

In 1900 the oil became very valuable and came to be called "Black Gold". In addition to being used as fuel, various products are derived from petroleum such as paraffin, natural gas, LPG, asphalt products, petrochemical naphtha, kerosene, solvents, fuel oils, lubricating oils, diesel oil and aviation fuel.

All of this influenced the production of preducts and consumption by them became increasingly large.

The one that  best represents the global spread of US culture through the entertainment industry was: Marilyn Monroe
The movies starred Marilyn Monroes ( such as  some like it hot  or the seven-year itch) were really big on the international market. The viewers of that movie were directly introduced to United States' culture simply by observing the actions of the actors and actresses