In 1956, uprisings behind the iron curtain occurred in

  Poland and Hungary

Explanation:

  The Iron Curtain was the physical boundary that divided Europe into two separate areas. From the end of World War II until 1991.

  In 1956 the Hungarian Uprising was a nationwide revolution against the Hungarian People´s Republic and the Soviet-imposed policies. It was the first major threat to the Soviet Union since World War II.

  In Poland, also in 1956, there were a series of protests against the communist government of the Polish People´s Republic. It began with workers demanding better working conditions and were met with violent repression.

  I hope this answer helps you.

answer: mickey mouse

explanation:

the main reason that the constitution did not proclaim all men to be free and equal is because of the issue of slavery.