physical/natural
famous fringing coral reefs
BARRIER - a blocking or physical interposition (e.g. "moisture barrier""Great Barrier Reef")
The Great Barrier Reef
the Great Barrier Reef off the coast of Austrailia.
Great Barrier Reef
the great barrier reef
The proper noun Great Barrier Reef is a concrete noun, a word for a physical thing.
no
Great Barrier Reef in Australia
George Clooney
Physical: What is inside the pyramid, what is surrounding the pyramid
The Great Barrier Reef