In the center,at ground level, is a round pool of water.
VOA: special.2009.05.25
Later,we visit rooms below ground level.
VOA: special.2009.11.16
And the fields are commonly divided between level ground and a mountainside.
VOA: special.2010.04.13
WMO scientists assess and monitor air pollutants such as ground-level ozone,smog, particulate matter, sulfur dioxide and carbon monoxide.
VOA: standard.2009.03.23
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