Question: when did the grand canyon became a national monument
[{'answer': '1908', 'provenance': [{'wikipedia_id': '46986', 'title': 'Grand Canyon National Park', 'start_paragraph_id': 4, 'start_character': 685, 'end_paragraph_id': 4, 'end_character': 689, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '46986', 'title': 'Grand Canyon National Park', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 980, 'bleu_score': 0.9604296978696261, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11034466917172699707}, 'section': 'Section::::History.\n'}]}]