Earthships are built from salvaged waste that can easily be sourced – glass bottles, aluminium cans, old car tyres and reclaimed timber are all key to the construction process. In many Earthships, you'll find hundreds, if not thousands of tyres, packed with dirt to create rammed-earth bricks.

Proving natural insulation, tyres are also regularly discarded after use. In fact, Earthship Biotecture suggests that at least 2.5 billion are currently stockpiled in the United States, with 2.5 million more discarded every year.

Recycled bottles are also a huge feature and allow natural light to flow inside the structures, creating a beautiful mosaic of glowing coloured glass.

Take a look inside the recycled homes designed to keep bills low