Oct 31 2026
A stream disappears into a hillside, a grassy hollow has no obvious outlet, and a hillside conceals a network of caves. These features may appear unrelated, but they can all belong to the same kind of landscape: karst. In karst country, understanding what happens underground helps explain the scenery above it. Karst is a landscape …
Oct 30 2026
A sinkhole can be a shallow hollow in a field, a deep opening surrounded by forest, or a dark circle of water in a tropical reef. Some develop so gradually that their changing shape is difficult to notice. Others appear suddenly when the ground loses support and collapses, bringing an underground process dramatically into view. …
Oct 29 2026
A limestone pavement is an area of exposed limestone divided into blocks by deep cracks and fissures. From a distance, its pale surface can resemble a huge stretch of uneven paving. Look more closely, however, and the pattern reveals a natural landscape shaped by the structure of the rock, the movement of ice, and the …
Oct 28 2026
A river can flow through a valley, enter a rocky opening, and vanish from the surface. Elsewhere, the change is less dramatic: the channel gradually loses water until only a dry bed remains. Both situations reveal a connection that is easy to overlook when looking at a map—the connection between rivers and groundwater. Some rivers …
Oct 27 2026
Limestone towers rising above a river, forests of sharp stone pinnacles, and vast caverns beneath wooded hills can all belong to the same family of landscapes. Known as karst, these places develop as water dissolves soluble rock and finds pathways through it. Their appearance varies enormously, from exposed rock pavements to islands surrounded by the …
