Albert Einstein Einstein did not return to Germany. He settled in the United States and became an American citizen in 1940. On the eve of World War II, he endorsed a letter to President Franklin D. Roosevelt alerting him to the potential development of "extremely powerful bombs of a new type" and recommending that the US begin similar research. This eventually led to the Manhattan Project. Einstein supported the Allies, but he generally denounced the idea of using nuclear fission as a weapon. He signed the Russell–Einstein Manifesto with British philosopher Bertrand Russell, which highlighted the danger of nuclear weapons. He was
Albert Einstein in popular culture Geisler presented the project on Kickstarter in collaboration with the Sigmund Freud Museum (Vienna) and the Albert Einstein Archives. Supporters of the project could choose to either receive the letters themselves or send them to politicians typeset in the handwriting of Einstein and Freud. Einstein is an integral character in the , being responsible in "" for altering the course of history using a time traveling device he created to remove Adolf Hitler from existence in an attempt to prevent the horrors of World War II, inadvertently leading to Soviet Union's rise to power and conflict with Europe. He continues