A device that lets you see through walls has been developed by a British company as the first of its kind. The device, called the Prism 200c, is small enough to fit inside a backpack. According to The Daily Mail, "The Prism 200c looks through solid objects then displays an image of what is on the other side on a hand-held screen."
The Daily Mail has more details:
Makers Cambridge Consultants expect it will be used by law enforcement agencies, emergency services or soldiers in ‘high-risk and hostile situations with minimal time and very narrow margin for error’.
The Prism can see through wood, concrete or bricks and gives a 3-D image of any movement inside the building.
Users stand with their back to the wall as the machine scans using ultra-wideband radio frequencies then look at the display to see what is going on.
The machine can also be linked up remotely to computers so commanders back at base know what is going on.
Ultra-wideband, also known as pulse radio, is very hard to detect and is able to work in a large area.
Read more here.