Question: when did the last known civil war veteran died
[{'answer': '1953', 'provenance': [{'wikipedia_id': '378367', 'title': 'Last surviving United States war veterans', 'start_paragraph_id': 45, 'start_character': 36, 'end_paragraph_id': 45, 'end_character': 40, 'bleu_score': 1.0, 'section': 'Section::::19th Century.:American Civil War (1861–1865).\n'}]}]