Celestial Basilica

The Celestial Basilica was where the High Hierophant of Five Revealed Truths was crowned. To commemorate the occasion, there was perfumed rain from clouds of powdered diamonds. The Doctor got an invitation to see it, but put it off for 300 years. He eventually went to see it in his fifth incarnation with Nyssa, but they were waylaid. (AUDIO: 1001 Nights)