An Iceberg is one thing, but a Fatberg is quite another.
A small town in England has been having issues with their pipes. When workers went into the sewage system to check it out, they came across a GIANT Fatberg. What is a Fatberg you may ask? It's a giant blob of fat from oil poured down the drain mixed with other miscellaneous things that people have dropped down their toilets or sinks. It blocks the sewers and causes big, stinky problems.
The last one found in the US was last year in Detroit's sewer system, measuring 100-feet long.
THIS is why your mother taught you not to pour oil down the sink! Mummy is always right.