A disgusting mystery has just been solved in Baltimore where a remote-controlled camera has discovered a blockage so big in one of the city's sewer mains, they're calling it a "fatberg."

A "fatberg" is a disgusting accumulation of fat, oil and cooking grease with a lot of baby wipes, condoms and other debris mixed in for good measure.

The fatberg in Baltimore is so big it is blocking 80% of a 24" sewer main near Penn Station. The clog may have taken decades to form.

It has also caused a 1.5 million gallon raw sewage spill into the nearby Jones Falls stream.

Baltimore Public Works officials say the spill has been stopped, but they have not settled on a strategy for removing the clog.

Sometimes the only way to remove a "fatberg" is by hand.

Public works officials across the nation increasingly view "fatbergs" as a major challenge, in part because the accelerated use of "flushable" wipes seems to help them form.

Baltimore officials are appealing to citizens to never pour cooking grease down drains. The appeal is echoed by utilities throughout the region. For instance, the WSSC has produced a video on the subject called "Can the Grease".