Question: where have the most olympic games been held
[{'answer': 'London', 'provenance': [{'wikipedia_id': '11015817', 'title': 'List of Olympic Games host cities', 'start_paragraph_id': 1, 'start_character': 558, 'end_paragraph_id': 1, 'end_character': 564, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]