The Uru trace their origins to a time before the Inca Empire, when they spoke their own language and lived apart from the highland civilizations that surrounded Lake Titicaca. They may have fled to the reed beds to escape hostile tribes, including the Incas themselves. Over the generations, their language gave way to Aymara, but their way of life on the water persisted. The islands are built from tortora rushes -- the same plant that provides the walls and roofs of their houses, the hulls of their boats, and even food. The white inner core of a fresh reed is edible, with a mild, slightly sweet taste that visitors are often invited to try. Before the 1980s, the islands were scattered along remote stretches of shoreline, with families sometimes living kilometers apart. Today they cluster in two dense rows along a river-like channel east of Puno, forming a floating town.

The Uros Islands have never been static. By some accounts, the community relocated in the 1980s partly to escape the violence of the Shining Path insurgency. A devastating storm and flood in 1985-1986 forced most of the islands to be rebuilt entirely. Their current position along a sheltered channel reflects a harder truth: Lake Titicaca's water levels have been dropping due to climate changes, leaving former reed beds high and dry. The naturally floating root mats that once served as island foundations have grown scarce, and the largest reeds suited for construction are harder to find. Traditional reed huts are gradually giving way to wooden structures and sheet-metal roofing. Some families have abandoned the floating platforms altogether, building stilt houses directly on the low riverbanks. What once floated freely now clings to a narrowing ribbon of water.

The Uros Islands carry a reputation as one of South America's most notorious tourist traps, and visitors who arrive unprepared may feel ambushed by souvenir pitches and unclear pricing. Each island receiving day tours follows a familiar template: an interpretive demonstration, rows of handicraft stalls, and oversized decorations fashioned from tortora reeds. But dismissing the experience as inauthentic misses the deeper story. The floating islands are real, maintained the same way they have been for hundreds of years, with fresh reeds layered over old. Tourism became the economic lifeline as fish stocks declined and young Uru moved to the mainland for education and jobs. Middle-aged residents sometimes lament that younger generations can no longer hunt or fish. The giant double-hulled reed boats that ferry tourists between islands were inspired by the designs of Bolivian reed-boat expert Paulino Esteban, who built similar vessels for Thor Heyerdahl's trans-oceanic expeditions in the 1970s. Newer versions are reinforced with recycled plastic bottles and fiberglass to extend their lifespan beyond the single year a pure reed boat survives before becoming waterlogged.

Staying overnight on a Uros island reveals a different world from the daytime tour circuit. The channel quiets after the last boats return to Puno, leaving the sound of water lapping against woven reeds and the occasional call of a wetland bird. At dawn, if the lake is calm, fishermen head out in the fading darkness while the first light spills across the altiplano hills. The Titicaca Grebe, found only on this lake and a few others in Bolivia, dives among the reed beds. On the island of Qananpacha, a small post office -- claimed to be the only floating post office in the world -- lets visitors send postcards from what feels like a place outside of geography. The accommodations are basic: reed-walled rooms, meals of fresh trout prepared in island restaurants, and cups of muna mate, a minty herbal tea said to ease the effects of the 3,800-meter altitude. The ground never quite stops moving.