Once upon a time, someone thought it'd be a good idea to dump millions of car and truck tires into the Atlantic Ocean. 

In 1972, environmentalists believed they could use the piles of rubber to create an artificial reef off the coast of Fort Lauderdale, Florida.

Now, the enormous tire piles on the ocean floor are considered a huge environmental mistake and taxpayers are spending nearly $2 million to clean it up. 

Phil Keating reported the strange but true story on "Happening Now," explaining that the "tire reef" idea would be unheard-of today. 

An armada hauled the tires out to sea more than 40 years ago, dumping load after load to the bottom of the ocean. 

One diver said that the tires are now slowly moving toward a pristine reef and preventing natural growth. 

Keating said decades ago, tires used to end up in giant heaps in landfills before efforts to recycle the rubber started in the 1990s.

Once the old, sunken tires are pulled out, they are burned in a power plant incinerator, which then produces green electricity.

20,000 have been removed since May, with a lot more work to be done. Officials hope to remove about 100,000 over the next few years.

Watch Keating's report above.