[You Need a Thneed]

Originally Posted by cracher

Another anecdote to express a cool story bro: had a house in scenic acres (1980s construction). The living room was huge, so I used a 220 gallon fish tank on a heavy rosewood base in the middle to sort of form 2 separate areas. 2 years later, we were playing with marbles and noticed that no matter where you dropped them, they rolled towards the fish tank. Using a laser leveller, we figured that the floor in the middle was a full inch lower than by walls. Good thing I got divorced and lost that house.

About 1800 lbs of water alone in that tank. Remove the tank, and the floor likely springs back up.