reporter: and lightning interrupting the search. now the president of the condo association north complex, the tower identical to the south tower, but completed one year later. everybody was scared. reporter: at the north tower, focus on maintenance borders on obsession. everybody says this is a twin building of the other one and that if something happens to one, it might happen to this one too, but it is not further from the truth. reporter: he and his team gave cnn access to the garage, pool deck, roof of his building. in the garage, no signs of cracking, no exposed rebar, no water or any moisture at all. sump pump designed to pump water from the garage brand new. water proofing on the pool deck overhauled, even planters on the pool deck are designed to prevent erosion and sinking. on the roof, every fixture, wire covering sealed to repel water. from that vantage point, you