This thesis analyzes, through the depiction of a 48-hour global event, two decades of evolution in modern finance. On October 19, 1987, stock market crashed in 23 countries around the world and the loss remains one of the most dramatic one-day market declines. The 1987 crash was completely forgotten since it had had no apparent consequences on the world economy. This work rehabilitates the event as the first global and modern crash that announced all the following crashes. Black Monday serves as a proxy to observe the geopolitical, legal, sociological, technological and cultural transformations of the financial world since the collapse of the Bretton Woods agreements through a transnational perspective. The thesis identifies an alternate geography of modern financial globalization and analyzed the performative representations prevailing in financial milieus through a prosopographic database of almost 3,000 financiers from more than 20 countries involved in brokerage firms, merchant banks, commercial banks, and asset management firms active in October 1987.