Where is the biggest indoor arena in the world?

Where is the biggest indoor arena in the world?
Current arenas

Arena
Capacity (max.)
City

KJC King Dome
75,000
Davao City

Philippine Arena
55,000
Bocaue

Saitama Super Arena
36,500
Saitama

Smart Araneta Coliseum
30,000
Quezon City

Current arenas
Arena Capacity (max.) City
KJC King Dome 75,000 Davao City
Philippine Arena 55,000 Bocaue
Saitama Super Arena 36,500 Saitama
Smart Araneta Coliseum 30,000 Quezon City