The Forest Service is protecting the area from too much human activity so it will return to its natural wild condition.

VOA: special.2009.07.20

It may look like a natural environment of lakes and woodlands, but it was entirely built by human labor.

VOA: special.2009.10.30

Experts explain that the movement of air in the atmosphere and natural qualities of the human eye caused him to see markings that were not there.

VOA: special.2010.07.11

These substances can damage the human nervous system and natural defenses against disease.

VOA: special.2009.06.23

Human development or natural disasters can change that environment.

VOA: special.2010.04.06

Some estimates suggest species extinction because of human activity is about 1,000 times faster than the natural rate of loss.

VOA: standard.2010.01.31

The architectural photographer says Machu Picchu is an example of how human and natural environments can exist in a well-designed and visually cohesive whole.

VOA: standard.2009.12.15