Question: when did caesar's palace open in las vegas
[{'answer': 'August 5 , 1966', 'provenance': [{'wikipedia_id': '48729052', 'title': 'Caesars Palace', 'start_paragraph_id': 7, 'start_character': 38, 'end_paragraph_id': 7, 'end_character': 53, 'bleu_score': 1.0, 'section': 'Section::::History.:Early history.\n'}]}]