A sinkhole, also known as a sink-hole, sink, swallow hole, shakehole, swallet or doline, is a natural depression or hole in the Earth’s surface which may have various causes. Some are caused by karst processes—for example, the chemical dissolution of carbonate rocks or suffosion processes in sandstone. Others are formed as a result of the collapse of old mine workings close to the surface.
What could have been the purpose of these enormous artworks etched into the landscapes all around the globe?
Lake Hillier, is a lake on Middle Island, the largest of the islands and islets that make up the Recherche Archipelago, Western Australia. The most notable feature of this lake is its pink colour. It is such a significant distinguishing feature of the archipelago that air passengers often take note of it. The colour is permanent, and does not alter when the water is taken in a container.
Impresionante video showing the eruption of the volcano Popocatepetl. There you can hear the loud noise accompanying the disposal of ash clouds in the sky.
The waters off Iceland rank among the world’s most productive fisheries. The reason for the abundance is an ample supply of phytoplankton, the base of the marine food chain. Like any plant, microscopic phytoplankton need sunlight and nutrients to survive. Iceland’s coastal waters offer both during the long days of summer.
Our understanding of what lies beneath the world’s biggest ice sheet has taken another leap forward. In this video we strip away Antarctic ice to reveal a new, and much more detailed map of the bedrock below. This map, called Bedmap2, was compiled by the British Antarctic Survey and incorporates millions of new measurements, including substantial data sets from NASA’s ICESat satellite and an airborne mission called Operation IceBridge.