The world's largest delta-style 3D printer stands 40 feet tall and can "print" a house from mud for around $50. The homes take advantage of the natural insulating properties of earth, and they can be made for close to zero cost using locally available materials. The 3D printer can lay down around three feet of mud each day, pausing at certain intervals for doors and windows to be manually installed. Hundreds of thousands of people are in need of new housing structures each year, according to the United Nations, and solutions like these could address the issue.

Water is essential for life, but it can be hard to come by in the Gaza region. One local man took his water needs into his own hands by creating a DIY solar desalination machine that can generate 2.6 gallons of fresh water in a single day. Fayez al-Hindi built a simple distillation tank on his roof that separates clean water from pollutants and salt, which supplies his family with just enough fresh water for their daily needs. Taking his DIY effort a step farther, al-Hindi also helps other local residents build their own distillation systems, since 90 percent of the local drinking water is considered unsafe for human consumption following decades of Israeli-Palestinian conflict.

In many of the hottest places on Earth, electricity is rare or inconsistent, which means air conditioning as we know it is simply not a thing. However, it's still possible to reap the benefits of cool air indoors with this incredible DIY device made from plastic bottles. In Bangladesh, Ashis Paul developed an air conditioner that involves a square board cut to the size of a window, through which empty plastic bottles are mounted. The Eco Cooler system is hung over a home's existing open window, and the plastic bottles catch the passing breeze and literally funnel it indoors, creating a gently soothing flow of slightly cooler air. Amazing, the system is capable of lowering inside temperatures up to five degrees Celsius.

In another genius reuse of plastic bottles, the My Shelter Foundation discovered a way to use them to light up Manila's slums, where electricity is hard to come by. A plastic bottle filled with water and a little bleach can be mounted through a home's rooftop, transforming it into a solar tube that draws in and disperses daylight. Homes that were once shrouded in complete darkness -- even in the middle of the day -- become flooded with light. This simple DIY project costs next to nothing, yet has a profoundly positive impact on the quality of life for people who were previously stuck living in the dark.

If you're lucky enough to have a washing machine in your home, you probably take for granted how easy it is to turn dirty clothes into clean clothes in the time it takes to binge watch a few episodes of your favorite Netflix show. Much of the world's population is still forced to wash their laundry in a river or stream, though, which is a laborious and time-consuming process. Remya Jose, a 14-year-old from India, invented a washing machine powered by bicycle pedals which uses a minimal amount of water and just a little human elbow grease to scrub clothes clean. Her device is extremely simple, yet it can save people huge amounts of time and energy -- which they can invest in other areas of life. Now in her mid-20s, Jose works at India's National Foundation, where she creates new inventions to help rural communities in her home country.

West African inventor Kodjo Afate Gnikou wanted to make a 3D printer, but couldn't afford the parts. So he found them. He sourced materials from broken scanners, computers, printers and other e-waste to build a working 3D printer that costs around $100 -- just a fraction of the price of commercially available models. The inventor belongs to the local hackerspace WoeLab, and he is working to make machines from recycled e-waste to prepare for missions on Mars. Diverting e-waste from landfills is a huge local win, but creating a functional tool out of garbage makes the innovation even more valuable. Through his upcycled inventions, Gnikou aims to "put technology into needy hands and give Africa the opportunity... to play the first role in a more virtuous industrial revolution."