Thanks to Kevin Dixon for the link to this amazing story on scanning the world’s largest natural underground chamber. Located in Borneo the Sarawak Chamber, part of the Mulu Caves was recently laser scanned by Kevin and his team.
The results indicate a circle of 325m diameter can be fit into the floor plan of Sarawak Chamber. This exceeds the Dallas Cowboys Stadium which is the largest unsupported, man-made dome structure at 275m in diameter.
You just can’t top Mother Nature.