In the 1970s in Taos, New Mexico, architect Michael Reynolds began building homes out of trash, starting with an experiment called the Thumb House. His rules were simple: use sustainable, indigenous, or recycled materials, run entirely on natural energy, and keep the design simple enough for someone with no construction skills. The result is the Earthship, a horseshoe-shaped home facing 10 to 15 degrees east of south, built from discarded tires packed with dirt by two-person teams until each weighs up to 300 pounds. Gaps are filled with squishies, interior walls are made of tin cans set in concrete and plastered with adobe, and the packed tires resist fire because they hold almost no oxygen.

An Earthship follows six principles, from solar and wind power run through a Power Organizing Module to rainwater used four times: once for drinking and showering, twice in an indoor botanical cell that grows food, and once more to flush the toilet. Thermal mass, Trombe walls, and a buried cooling tube keep rooms near 70 degrees, but in cloudy Europe the uninsulated walls lost heat and grew mold until a 2015 build with the Fraunhofer Institute in Germany added insulation. Permits have been a constant fight, chronicled in the documentary Garbage Warrior, including a Belgian mayor’s veto in 2000 while Reynolds’s team was on the way.

• How the Water Organization Module filters roof water from a cistern into pressurized, drinkable tap water
• Why black water from the toilet goes through an anaerobic digester and should never feed edible crops
• Packed soil’s R value of about one per foot, meaning a 13 foot wall to match a standard fiberglass roll
• The Lizard, a proposed 16-home Brighton development using 15,000 tires in a country that burns 40 million a year
• Earthships in South Africa, Sierra Leone, Ushuaia, Uruguay, Argentina, Australia, and Belize, and fears of lead and zinc leaching from tires