Now, there's an effort afoot to make it vanish, launching from the shores of San Francisco Bay.
"When I was 16 years old, I was SCUBA diving in Greece. I saw more plastic than fish, and I thought, 'Why can't we just clean this up?'" said Boyan Slat, founder of The Ocean Cleanup.
Slat is now 23, and that innocent question has since become his full-time job -- about 80 to 100 hours per week, he estimates.
His organization's bold aim to clean up the world's oceans is starting with perhaps the boldest undertaking of all: the spot between California and Hawaii known as the Great Pacific Garbage Patch: an area three times the size of France filled with swirling plastic debris, trapped by the ocean's currents.
They're fighting plastic with plastic! @TheOceanCleanup took us for a tour of its first system to collect and remove garbage in the Pacific. The floating tubes are made of HDPE plastic: the same material as much of the trash they'll collect. pic.twitter.com/zmEAIxKsHI— Jonathan Bloom (@BloomTV) April 18, 2018
"As far as we know, we are the first that are really going to actively try to remove plastic from the high seas," said Ocean Cleanup spokesperson Joost Dubois.
The project starts with a giant plastic pipe -- shipped to the shores of Alameda in 40-foot sections and fused together into a long, snaking tube of HDPE plastic -- the same material as most of the garbage it will collect.
Filled with air, the tube will float on the ocean's surface, with a nylon screen hanging below it -- to keep the fish out, and the garbage in. Crossed cables will bend the tube into an arc, forming a giant floating dustpan that doesn't need a broom. The sweeping is done by the ocean itself.
"Because why would you go after the plastic if the plastic can also come to you?" Slat said.
When the first system is put in the water for a test just outside the Golden Gate, it'll be about 400 feet long, and if it works, the team will keep extending it to 2,000 feet. But that's only the beginning: when the final systems are floated out into the Pacific ocean, there will be 60 of those giant floating scoops, each stretching a mile from end to end.
Dubois says with boats coming to collect garbage every six to eight weeks, the scoops could collect half of the plastic debris within five years, and 90 percent of it within two decades. The project already has $40 million in funding from investors including Salesforce founder Marc Benioff. It will need hundreds of millions more -- funds the team says will be easier to get once they've demonstrated some success.
"The hardware is getting very, very real -- but we still have to prove that it works," Dubois said.
The first open ocean test could happen as soon as July. The systems will float without power on the ocean's current, collecting garbage until boats come to empty them out and bring the contents home for recycling. The first plastic to arrive on shore will be a major milestone for the cleanup effort, Slat said.
"We as a humanity created this problem, so I think it's our responsibility also to help solve it," he said.