AZUZ: Gyres are natural, but some of the stuff swirling in them isn`t. Garbage, trash from nations, shorelines, boats, collected in currents swirling around the oceans. The Indian Ocean search for a missing Malaysia Airlines passenger plane has been called "the most difficult search in human history". Gyres of garbage are making that search even harder.

UNIDENTIFIED MALE: Debris that you might see in our homes or around our homes, here`s a toy grenade, here`s a paintbrush handle, here`s a toy leg from a baby. Flip flops.

RANDI KAYE, CNN CORRESPONDENT: Not items from a landfill. But from the ocean. More specifically, the Indian Ocean gyro. Essentially, a garbage patch swirling with trash and overflowing with plastic. The massive rotating current spins counter clockwise. Marcus Eriksen is the director of research for the Five Gyres Institute in California. He says gyros are like plastic soup.

MARCUS ERIKSEN, 5 GYRES INSTITUTE: But that`s typical of what the material looks like.

KAYE: In 2010, he sailed through the Indian Ocean gyro, the same area where search teams are now looking for doomed flight 370.

ERIKSEN: What we found there, were things like derelict fishing nets, multicolored buoys, all fishing buoys like the one that`s behind me. Lots of buckets and crates, other consumer goods like bottles. And bottle caps. And bags and forks and knives. There was so much stuff already there. So the aircraft and debris from the aircraft is blending into all that.

KAYE: Which is one reason why locating the missing plane is such a challenge. Satellite images once thought to be debris fields, likely just floating garbage. A Chinese ship just this week in search of the airplane came across trash instead. Even sea life can`t tell the difference. Fish, sea lions, birds, they all ingest this junk thinking it might be food.

ERIKSEN: You know, to hear this talk about there are being 300 plus pieces from the aircraft. There are 300,000 plus pieces of trash already there.

KAYE: The Indian Ocean gyre isn`t the only one that exists. There are also two in the Pacific and two in the Atlantic. They form when ocean currents bounce off the continents and create a vortex of swirling water, which posed debris from the shores to the center of the ocean.

The gyro in the Indian Ocean is thought to be about 2 million square miles. Now, keep in mind, the entire United States is just under 4 million square miles. And this garbage patch isn`t just huge, it`s also on the move, traveling about half a mile per hour or about 12 miles per day. And it may be carrying parts of the plane with it.

AZUZ: Leonardo da Vinci sketched a flying machine in 1485, but, of course, he never flew in one. 2 Frenchmen climbed aboard the first untethered balloon in 1783, but didn`t exactly power it. Even the Wright brothers at the dawn of powered flight, didn`t have to flap or pedal themselves. You might say these folks, compared to the men you`re about to meet, took the easy way up.