In t­he northern Pacific Ocean, there exists the North Pacific Subtropical Gyre, a slowly moving, clockwise spiral of currents created by a high-pressure system of air currents. The area is an oceanic desert, filled with tiny phytoplankton but few big fish or mammals. But the area is filled with something besides plankton: trash, millions of pounds of it, most of it plastic. It's the largest landfill in the world, and it floats in the middle of the ocean.

The gyre has actually given birth to two large masses of ever-accumulating trash, known as the Western and Eastern Pacific Garbage Patches, sometimes collectively called the Great Pacific Garbage Patch. The Eastern Garbage Patch floats between Hawaii and California; scientists estimate its size as two times bigger than Texas [source: LA Times]. The Western Garbage Patch forms east of Japan and west of Hawaii. The patches are connected by a thin 6,000-mile long current called the Subtropical Convergence Zone.

The garbage patches present numerous hazards to marine life, fishing and tourism.