Conversation so far:
What happened with the Taiwanese band?
During their hiatus, Mayday released the autobiographical documentary titled The Wings of Dream <<Yao Gun Ben Shi >> .
Was this a bestselling book?
with ticket sales hitting more than NT1.2 million in barely three days.
Did it continue to sell that way?
They also released an accompanying soundtrack.
What happened with the return to the music scene in 2004?
To mark the event, Mayday held their City of the Sky <<Tian Kong Zhi Cheng >>  concert on 16 August 2004 at the Taipei Municipal Stadium.

Question: How many people attended the concert?
Self-contained rewrite: How many people were in attendance at Mayday's concert on 16 August 2004 at the Taipei Municipal Stadium?