As war began to spread across Europe, many realized that their lives were in danger. Growing intolerance made it necessary to search for a safe haven outside of Europe, and the United States found itself home to much of this immigration. Among those who came were artists, scientists, and intellectuals whose visibility made it even more necessary to leave their homelands. This influx, which included among it many of the experimental modern artists, was a major turning point in the elevation of New York as the center of the international art world. The most famous of these immigrants was scientist Albert Einstein. There were other American Masters as well, including musician Arthur Rubinstein, artist Man Ray, photographer Andre Kertesz, and writer Isaac Beshevis Singer. Though their embrace of the United States was often tentative, these immigrants invigorated their cultural and intellectual worlds in ways the country had never experienced.