i shot it wide just so we could see those things. you have the guys on top, who are listening and checking with a probe. >> yes. >> and then, in the middle, they have de-layered, as you guys call it. and they've blocked it up with wooden blocks and then they send in a sensor or a camera and then a dog. >> correct. >> and they said that they'd been doing that, spot by spot. this is the process. >> absolutely. so, there is just a few of them on top. they're using a delsar system, which is a listening device. and actually, they can pick up sound, scratches, back-and-forth movement. so they're trying to pick up that location. the rescuers were able to pick up that side of the pile. what you said with the wood, being able to secure that area. and then, send the canines in. if a canine gives a hit or a live hit on possibly a person being inside there, they will always confirm it the second time. and that will be putting in a camera, search camera, and being able to communicate with that person, and/or visualize that person.