Regional diversity affected the development of Islam because as Islam spread it went to numerous culturally diverse regions. These regions and peoples adopted Islam and developed the religion differently. From regions as wide as West Africa to Indonesia, Islam took on unique forms because of the people who took up the religion and adapted the religion along the way.
Wilson wanted to created lasting peace across nations, so aimed for the creation of the League of Nations(later known as UN). The United States never joined it, and many people didn't want the country getting involved in foreign affairs
I'm not sure what you mean by "historically", but there are many key features of London:
Big Ben
Buckingham Palace
the Thames River
London Bridge
London Eye
Trafalgar Square
Hyde Park
Westminster Abbey
the Globe Theater
