this is to protect tokyo, located north of tokyo in kusakabi, jaen. >> the city starts get flooded andrain water. this thing kicks in and throws it back out. >> that's exactly what it is. this is a nearly four-mile structure that is 50 meters beneath the surface of the ground. it's five concrete silos, a large water tank and 59 pillars that are connected to a number of pumps. and these pumps can pump 200 tons of water per second. >> imagine the manpower and the man hours that went into making that. >> they started building it in 1992. >> it looks spooky, like something from a video game. that's weird. >> you know what would make it creepier, spider webbs. >> robots. >> don't go there. >> this is where all the robots will come hide when they amass their army and then boom, watch out, steven. >> don't get me started on that. >>> hedge hog bath time. ♪ >>> it's that time of the show to tell you about what we'll share with you tomorrow on "right this minute." it's a story of a family that stays together because they fly together. no one is left out, especially this guy. brodie. tomorrow on