From literature genius Mark Twain and Nikola Tesla's friendship to Susan B. Anthony and Elizabeth Cady Stanton's friendship that was pivotal in granting women's right to vote in US or Franklin D Roosevelt and Winston Churchill's bond during World War II or Microsoft Co-Founders Bill Gates and Paul Allen's friendship that revolutionised the personal computer industry, famous friendships have had profound impacts on history - shaping cultural, political and scientific developments. On the eve of Friendship Day this year, here are some notable examples of friendships that not only shaped the lives of the individuals involved but also had lasting impacts on society, culture, politics, science and technology across the world -