The correct answer is cars.
The development of the Eisenhower Instate System during the 1950's resulted in the creation of an enormous amount of interconnected freeways and highways throughout the United States. With these new roads available, there was a significant increase in buying cars. This is because now citizens could travel from city to city and state to state on a much easier basis than ever before.
The most closely related to the Mexican- American war is the Romantic Period