Unfortunately, the most common form of land mine detection is unintentional. It involves a poor civilian stepping on one and losing life or limb, and it's a pretty awful situation in many third-world countries. With 60 to 70 million land mines laying undetected in 70 countries, the mine situation is an epidemic. But how to detect mines and get them safely excavated without hurting anyone?
A group of researchers at MIT have developed a device that shoots tightly focused acoustic beams capable of traveling underground. When a mine is hit, it pushes the dirt up around the area, making it visible on radar. Hopefully this device will get deployed to the places it's needed most and will save a lot of people from a seriously unpleasant end.