Question: what is one unique fact about lake tahoe
[{'answer': 'the clarity of its water', 'provenance': [{'wikipedia_id': '140899', 'title': 'Lake Tahoe', 'start_paragraph_id': 2, 'start_character': 154, 'end_paragraph_id': 2, 'end_character': 178, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'the panorama of surrounding mountains on all sides'}, {'provenance': [{'wikipedia_id': '140899', 'title': 'Lake Tahoe', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 463, 'bleu_score': 0.946458428441119, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17108596723211208738}, 'section': 'Section::::Abstract.'}]}]