Inside world's most extreme homes: Houses hanging from cliffs, built on rocks and hidden underground

This American house was built directly above a waterfall

Imagine hearing a waterfall flowing beneath your home. Fallingwater, in Pennsylvania, was designed by architect Frank Lloyd Wright in 1935. Built as a weekend retreat for the Kaufmann family, the house stretches out over a natural waterfall, surrounded by forest. The family used it for decades before it became a museum open to visitors.

An Iranian village where entire homes are carved into rocks

Iran's Kandovan village is famous for its unusual homes carved into cone-shaped volcanic rocks. Generations of villagers have turned these natural formations into rooms, kitchens and living spaces. Unlike many ancient cave settlements that are now tourist sites, Kandovan is still home to local families.

Tunisia's underground homes protect families from desert heat

In southern Tunisia's Matmata region, families have lived in underground houses for centuries. These homes are built around deep, open courtyards, with rooms carved into the surrounding earth. Their thick walls protect residents from summer heat and cold winter winds. Although many families have moved away, some still live in these traditional homes.

An Australian town where people live beneath the ground

In Coober Pedy, Australia, many residents live in underground homes called dugouts. The desert town experiences extremely hot weather, so people have built houses inside the rock to escape the heat. These homes can have bedrooms, kitchens and living areas, just like ordinary houses. The surrounding earth helps keep indoor temperatures comfortable.

This Swiss home is almost completely hidden underground

At first glance, Villa Vals in Switzerland looks like a large hole in a grassy hillside. But inside is a modern home completed in 2009. Most of the building is hidden beneath the slope, while a curved opening lets sunlight enter. Visitors reach the house through an underground tunnel connected to a nearby barn.

A house built between four giant rocks in Portugal

Portugal's Casa do Penedo looks like something from The Flintstones. Built between four enormous granite boulders, the house opened in 1974 as a family holiday retreat. Instead of removing the rocks, its builders made them part of the structure. The unusual stone home has since become a tourist attraction.

These houses hang over the edge of a cliff in Spain

Spain's historic city of Cuenca has houses that appear to hang from steep cliffs. Known as the Hanging Houses, these medieval buildings overlook the Huecar Gorge, with wooden balconies extending over the drop. Some surviving buildings now house an art museum and a restaurant.

This Australian house stands on a single concrete pillar

Imagine living in a house that appears to float above the ocean. Australia's famous Pole House in Fairhaven stands on a 13-metre concrete pillar, high above the beach. Built in 1978 and later renovated, the house is reached by a narrow bridge and offers spectacular views of the sea.