East Germany decided to upgrade the fortifications in the late 1960s to establish a "modern frontier" that would be far more difficult to cross. Barbed-wire fences were replaced with harder-to-climb expanded metal barriers; directional anti-personnel mines and anti-vehicle ditches blocked the movement of people and vehicles; tripwires and electric signals helped guards to detect escapees; all-weather patrol roads enabled rapid access to any point along the border; and wooden guard towers were replaced with prefabricated concrete towers and observation bunkers. 
As West Germany was reorganised and gained independence from its occupiers, the German Democratic Republic was established in East Germany in 1949. The creation of the two states solidified the 1945 division of Germany.  On 10 March 1952, (in what would become known as the " Stalin Note ") Stalin put forth a proposal to reunify Germany with a policy of neutrality, with no conditions on economic policies and with guarantees for "the rights of man and basic freedoms, including freedom of speech, press, religious persuasion, political conviction, and assembly" and free activity of democratic parties and organizations.  This was turned down; reunification was not a priority for the leadership of West Germany, and the NATO powers declined the proposal, asserting that Germany should be able to join NATO and that such a negotiation with the Soviet Union would be seen as a capitulation. There have been several debates about whether a real chance for reunification had been missed in 1952.