What is a Floating Island?

One of the biggest tourist attractions of Lake Titicaca for once happens to correspond with a pretty genuine way of rural life for the locals - the Floating Islands. At first I thought that these Islands were all natural, and the locals had just decided one day to float around a big lake on a natural wonder as a way of life. But I was actually very surprised by the culture we found on these Urus Islands. 

About twenty minutes off shore by motorboat, we hit a huge shallow section of the lake that is filled with reeds and natural islands, and is "preserved" as a natural habitat for dozens of bird and fish species. It turns out that hundreds of years ago, the locals figured out that the roots of these plants produce a gas that keeps them afloat in the water, even under heavy weight and pressure. Because of the strength of the plant roots, the huge blocks of dirt that the plants grow in are not eroded by the water, nor does it weight the plant down whatsoever. No matter what, this plant, and anything attached to it, floats. With that knowledge, the people started building their own islands out of these things - they cut out huge bricks of mud and plant roots, group them together in bundles of four, put a stick in each block of dirt, and rope them all together with a piece of rope or string. They do this until they have built a floating platform able to house 8 to ten families, and then they cover this platform with cut reeds from the natural islands, layering these reeds until they're several feet thick and the dirt blocks underneath are completely submerged. On top of this sturdy little island they start building houses, kitchens, communal areas and fires, and all of a sudden, you have your own little isolated community!

The problem with floating islands is that, obviously, since they are floating, they tend to float away from each other. The prospect of always waking up in a new place may seem exciting, but in order to have any kind of consistently larger community, they started building several groups of little islands, loosely roping everything together under the water. The result? Urus, the large, thriving group of islands that we visited. They had an island for a market, an island for a school, an island for a restroom (which they periodically burnt and rebuilt), an island for a graveyard, and then a million little surrounding islands of small neighborhoods. Each people-group island had it's own name, with a large tower built which served as a means of communication - if you had anything to say to a neighboring island, you could shout from one island to another, wave your arms in hand signals, or use some type of smoke signals.

The funny thing about these islands was their adaptability. The houses were light and made out of reeds, with neither foundations nor any kind of weight to keep them down. If two families were especially close, they would face their kitchens and houses towards each other. If they got angry with each other, however, they would pick up their houses and turn them around, so that they were facing their backs to each other. And if the argument was really bad, you had two options: pick up your house, put it on a boat and float to a different island; or you could cut the island in two and float away from each other into two separate little islands. The second option was much more difficult, however, because cutting through four or five feet of reeds and then through another 3 and a half feet of solid dirt was pretty difficult. 

I finished enthusiastically explaining all this and much more to my Mom the other day while I was showing her some pictures, quite thrilled about this creative little people group who had built their own floating islands out of reeds for centuries, and she said,

"Huh. Why do they do that? Why do they build islands, instead of just living on the shore like everyone else?"

And I have no idea.