Final answer:
The Civil Rights Act of 1964 made discrimination based on race illegal in public accommodations and employment, significantly impacting U.S. civil rights laws.
Step-by-step explanation:
It was the Civil Rights Act of 1964 that made it illegal for railroads, hotels, and other institutions to discriminate on the basis of race. This landmark legislation outlawed segregation in public accommodations, employment discrimination, and was legally justified not by the Fourteenth Amendment's guarantee of equal protection of the laws but instead by Congress's power to regulate interstate commerce. The Civil Rights Act is considered one of the most significant civil rights laws in U.S. history, with far-reaching impacts on society.