I live near a few volcanoes. One of them – Mount St. Helens – is bubbling with molten material that will probably gush out as lava someday. I asked my friend Johannes Hämmerli about lava. He’s an ...

Far below your feet, nearly 1,800 miles beneath oceans and continents, Earth carries two massive scars from its violent youth. They are so large they rival continents in size, yet no human will ever ...