There was an abandoned farm about 1/2 mile from my house, has an old colonial home and a big cow barn. Some guy bought it 4 years ago and never lived in the house. He decided to sell and the guy across the street asked me for my opinion on market value, since I'm an appraiser and he wanted to buy it. Turns out the guy used the cow barn for growing weed. You could see the set up and it still smelled, in fact before I knew this, I could smell it most times I drove by. The building is about 30-70, seems like he was making good money. He ended up changing his mind about selling and going by the smell when I drive by got the business going again.