Posted on November 28, 2022 (Updated on July 9, 2025)
The longest cave on earth
Natural EnvironmentsYou’d better not get lost in its dark corridors: the labyrinth of the Mammoth Cave in the US state of Kentucky stretches a full 591 kilometres. That is about as far as from Karlsruhe to Kiel. This makes Mammoth Cave the longest known cave on earth. Its widely ramified network of passages and chambers runs
Posted on November 25, 2022 (Updated on July 9, 2025)
Thick air in mega-cities
Natural EnvironmentsWhether in Lagos, Tehran or Calcutta – in many cities and urban centres the population growth is enormous. Worldwide, there are currently already about 20 cities that have more than 10 million people, so-called mega-cities. Here, it is not only the number of inhabitants that is rising. With the growth, the environmental problems are also
Posted on November 25, 2022 (Updated on July 9, 2025)
Germany’s first offshore wind farm
Natural EnvironmentsAfter seven months of construction, Germany’s first offshore wind farm has gone into operation. “Alpha ventus” is the name of the 250 million euro facility located 45 kilometres off the North Sea island of Borkum. In the future, the wind farm will supply electricity for 50,000 households. Far off the coast they stand in 30-metre
Posted on November 25, 2022 (Updated on July 9, 2025)
The race of the rivers
Natural EnvironmentsThe Nile is the longest river on earth. Or is it not? Some researchers doubt this record and claim that the Amazon is longer. But it is not so easy to measure a river precisely. The previous leader was the African Nile with a length of 6,671 kilometres. It has its source in two headwaters:
Posted on November 25, 2022 (Updated on July 9, 2025)
Father Christmas comes in swimming trunks
Natural EnvironmentsThis year, too, it is far too hot for Father Christmas in Sydney. While we in Europe are keeping warm with biscuits and mulled wine, in Australia it is high summer temperatures at the same time – over 30 degrees Celsius. Unfavourable conditions for a Christmas as we know it. But the Australians stick to
Posted on November 25, 2022 (Updated on July 9, 2025)
The permafrost thaws
Natural EnvironmentsThe frozen soils of the Arctic are thawing faster than previously assumed due to climate change. This could release huge amounts of the greenhouse gas methane into the atmosphere. This would further accelerate the warming of the Earth. Permafrost soils extend over huge areas in the northern hemisphere. They are mainly found in large parts