Question: when was the grand canyon national park established
[{'answer': 'February 26 , 1919', 'provenance': [{'wikipedia_id': '46986', 'title': 'Grand Canyon National Park', 'start_paragraph_id': 3, 'start_character': 60, 'end_paragraph_id': 3, 'end_character': 78, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}]