Question: when was the leaning tower of pisa closed
[{'answer': 'January 7 , 1990', 'provenance': [{'wikipedia_id': '46889', 'title': 'Leaning Tower of Pisa', 'start_paragraph_id': 17, 'start_character': 38, 'end_paragraph_id': 17, 'end_character': 54, 'bleu_score': 1.0, 'section': 'Section::::History following construction.\n'}]}, {'provenance': [{'wikipedia_id': '46889', 'title': 'Leaning Tower of Pisa', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 824, 'bleu_score': 0.8576013061253701, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9981132734308186458}, 'section': 'Section::::History following construction.\n'}]}]