After 25 years, water seeps through the reeds and the inhabitants build a new island and let the old one sink to the bottom of the lake.

These dense roots that the plants develop and interweave form a natural layer called khili (about one to two meters thick), which are the main flotation and stability devices of the islands.

The blocks used to be harvested with eucalyptus wedges, but are now sourced using 1.5 m (4.9 ft) long metal saws custom made for this purpose.

Once the khili pallets are tied together and anchored, multiple layers of cut reeds are added.

Tourism via boats from Puno has become the primary financial income for people living on the islands.

[citation needed] The Uru's islands are located at 3,810 m (12,500 ft) above sea level, and just five kilometers east from the Puno port.

[7] Around 2,000 descendants of the Uru were counted in the 1997 census,[4] although only a few hundred still live on and maintain the islands; most have moved to the mainland.

Food is classically cooked in pots on pottery stoves; these are placed on flat stones to prevent the flammable reed islands from catching fire.

All houses are built on top of an extra 1 m (3.3 ft) layer of dry reeds to prevent rheumatism.

Uru also hunt birds such as seagulls, ducks and flamingos, and graze their cattle on the islets.

They also run crafts stalls aimed at the numerous tourists who visit ten of the islands each year.

The Uru do not reject modern technology: most boats have motors, nearly all islands have shared solar panels to run appliances such as televisions, and the main island is home to an Uru-run FM radio station, which plays music for several hours a day.

High ultraviolet radiation levels occur throughout the Altiplano region of Peru and Bolivia.

As of 2011[update], about 1,200 Uru lived on an archipelago of 60 artificial islands,[9] clustering in the western corner of the lake near the port town of Puno.