In the mid-1950s a Fortune editor came up with the idea of listing the biggest U.S. industrial companies. The idea stuck: The Fortune 500 is now arguably the most recognizable ranking of corporate America. As current Fortune editor Alan Murray explains in the video above, being on the list is widely seen as a hallmark of corporate prestige.
To build the list, companies are ranked by total revenue. That makes Walmart, with nearly half a trillion dollars in revenue last year, No. 1 on the list. Apple, which has a market valuation of nearly $750 billion — the highest on the list — ranks just 5th in revenue.
Despite the recent drop in the price of oil, energy companies still rank high on the list. Exxon Mobil is No. 2, and Chevron is No. 3.
The list has changed dramatically over the past 60 years, as this interactive graphic shows. But even in the age of Uber and other start-ups, the companies in the Fortune 500 still drive a big portion of the U.S. economy and remain, largely, the most important companies in America.