Transcript for Texas Lake Home Teetering on Cliff Set Ablaze
Imagine watching your dream home burn live on television. But not by accident. The family you are about to meet actually planned the building's bonfire. With the kids even making signs. Why? Here is ABC's Matt Gutman. Reporter: What do you do if your stately mansion on a bluff starts to fall? Piece by piece into the lake below. Set it on fire? I was surprised when heard, burn it down. When he mentioned burning it, it was a shock to the system. You know it was almost a relief because-up are watching bits and pieces fall. You are thinking, somebody could be down there and get hurt. What gravity started month as go this inferno finished today. They watched their dream home scorched on purpose. Horrible. It really is horrible. Reporter: With cameras all around it burned and burned. For nearly two hours. How surreal was that? Very surreal. Our friend are going this is horrifying. It's gut wrenching. Reporter: They bought their retirement home in 2012 hoping to stay there for the rest of their lives. I would pass it on to the grand kids. All said and done. Reporter: Little did they know, last appraised at $700,000 was constructed on limestone. Everyone said the ground was solid. Go for it. Yeah. Look ate. Solid rock. Looked like it was solid. You build your house on a rock you think it is okay. Reporter: Then cracks appeared in the walls and in the foundation and so they called in the geologists. The whole time the GE O was calling in, sending a message. Please leave the furniture in there. Get out. Condemning it. Going to happen. Reporter: Telling you to run for your lives. Right. Reporter: That was in February. In April parts began plopping into lake Whitney. Friday when the fire department intentionally torched their home, retirement plans went up in smoke. The one thing their insurance approximately see didn policy didn't cover landslide. The Earth moves in mysterious way. Especially here in Florida, where they had a condo. A sinkhole devoured this resort. And in Tampa, another sinkhole did much worse. Swallowing a man sleeping in his bed. The webs were grateful no one was hurt. The bright side of watching their house burn on TV, their grand kids had made a sign. In front of the firetruck third was. We love you, Nana and papa. Reporter: For "Nightline," Matt Gutman, in Miami. Thank you for joining us.
This transcript has been automatically generated and may not be 100% accurate.