Question: who plays the mountain in game if thrones
[{'answer': 'Hafþór Júlíus Björnsson', 'provenance': [{'wikipedia_id': '28344747', 'title': 'Hafþór Júlíus Björnsson', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]