The web was built specifically to share research papers amongst scientists. Despite this being the first goal of the modern web, most research is still published behind a paywall. We have recently highlighted famous math papers that reside behind a paywall as well as ten papers that have achieved a near rockstar status in research and the public. Here we systematically look at the top one hundred cited papers of all time and find that 65% of these papers are not open. Stated another way, THE WORLD’S MOST IMPORTANT RESEARCH IS INACCESSIBLE FROM THE MAJORITY OF THE WORLD. A few facts about the top 100 cited papers: 1. The weighted average of all the paywalls is: $32.33, rounding to the nearest cent. 2. There are 1, 088, 779 citations of the Open Access articles, so, if they cost the same on average as the Paywalled articles and were paid for individually, they would cost a total of: $35, 199, 108.44–that’s 14 Bugatti Veyrons, or enough to buy everyone in New York City a Starbucks Tall coffee and chocolate chip cookie. In comparison, the total amount for the paywalled articles, assuming everyone bought the paywalled articles individually, is $54, 722, 252.80. 3. That’s 23 Bugatti Veyrons, or enough to buy everyone in New York City a footlong from Subway. 4. Although 65% of the most cited papers are paywalled, only 61% of those paper’s citations are from paywalled journals. Thus the open access articles in this list are, on average, cited more than the paywalled ones.