Question: when did the berlin wall start to come down
[{'answer': '13 June 1990', 'provenance': [{'wikipedia_id': '3722', 'title': 'Berlin Wall', 'start_paragraph_id': 1, 'start_character': 407, 'end_paragraph_id': 1, 'end_character': 419, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3722', 'title': 'Berlin Wall', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 823, 'bleu_score': 0.7017940477036101, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5495364051185243599}, 'section': 'Section::::Abstract.'}]}]