Question: where does the word achilles heel come from
[{'answer': 'Greek mythology', 'provenance': [{'wikipedia_id': '380175', 'title': "Achilles' heel", 'start_paragraph_id': 3, 'start_character': 3, 'end_paragraph_id': 3, 'end_character': 18, 'bleu_score': 1.0, 'section': 'Section::::Origin.\n'}]}, {'provenance': [{'wikipedia_id': '380175', 'title': "Achilles' heel", 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 523, 'bleu_score': 0.9792717993254391, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8990387551720580054}, 'section': 'Section::::Origin.\n'}]}]