The correct answer is: "the Berlin Wall".
The Berlin Wall was built in 1961 in order to separate the Soviet-ruled Eastern part of the city that was comprised in the denominated German Democratic Republic, and the Western area of the city which had been put under the control of the Western Allied powers (UK, US and France) at the end of WWII and which was part of the Federal Republic of Germany at the moment of the construction of the wall.
In the Cold War scenario, the German Democratic Republic was under the influence of the URSS and therefore pertained to the Eastern bloc, while the Federal Republic of Germany was influenced by the US and the capitalist Western Powers. These two blocs, the Eastern and Western ones were divided by the so-called "iron curtain" (term used by Churchill).
<u>The Berlin Wall was a physicall barrrier that materialized the methaporical division expressed by the term "iron curtain".</u>
