If you've ever driven along a winding road in a steep gorge or ravine, you've probably looked up at the looming cliffs and wondered what a deadly, car-crushing rockfall would look like.
So have the people of Norway. They're so concerned about this threat in fact, that they've declared war on sheer rock faces. The soldiers in this war are helicopters, armed with wrecking balls that smash huge boulders off the cliffs:
This has to be one of the coolest forms of hazard mitigation I've seen, right up there with using a howitzer to induce controlled avalanches.
(ht: Ian O'Neill)