Most significant landforms, such as tall mountain ranges or deep canyons, are large features that stand out in bold contrast to their surroundings.
(Most significant landforms, such as tall mountain ranges or deep canyons; are; large features that stand out in bold contrast to their surroundings) (large features; stand out; in bold contrast to their surroundings)
Most significant landforms, such as tall mountain ranges or deep canyons large features
are stand out
large features that stand out in bold contrast to their surroundings
in bold contrast to their surroundings