Question: what symbol of soviet repression and terror fell in berlin in 1989
[{'answer': 'the Berlin Wall', 'provenance': [{'wikipedia_id': '4584893', 'title': 'Revolutions of 1989', 'start_paragraph_id': 2, 'start_character': 1149, 'end_paragraph_id': 2, 'end_character': 1164, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '4584893', 'title': 'Revolutions of 1989', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 1251, 'bleu_score': 0.784660258519501, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6161986861707704342}, 'section': 'Section::::Abstract.'}]}]