The Open Skies Treaty is in danger. Signed in March 1992, it has been in force since January 2002 and permits 34 states in Europe and North America, including Germany, to conduct unarmed observation flights over each other. The aim is to be able to observe military changes. In October 2019, several sources reported that Trump administration is considering to exit the treaty. Since then European allies and treaty supporters in the U.S. Congress have called upon the government to refrain from taking this step. On the website www.openskies.flights Dr. Alexander Graef and Dr. Moritz Kütt for the first time visualize the Open Skies Treaty overflights from 2002 to 2019 and show why the treaty is essential for Europe.