world war ii had left the city of berlin 100 miles deep within east german territory, controlled by the soviet union, and divided into soviet, british, french, and united states zones of occupation, administered under local agreements which did not guarantee western access to the city. responding to a series of soviet actions in 1948, the three western allies consolidated their zones and formed the city of west berlin. for fifteen years the western powers maintained a tenacious hold on west berlin under periodic harassment of the soviets. on 13 august 1961, berliners woke up to find they lived in a divided city. a wall now separated east berlin from west berlin. with that provocative act, the soviet union ratcheted up the cold war.