The Line is a proposed smart linear city in Saudi Arabia in Neom, Tabuk, currently under construction, which is designed to have no cars, streets or carbon emissions.

 The Line is being described as a one-building vertical city outfitted with exterior mirrors, big enough to house 9 million people — along with everything they need, from parks and waterfalls to flying taxis and robot maids. There are even plans to include an artificial moon for residents to gaze upon.

With its proposed width of only 656 feet, The Line will rely primarily on its height to encompass its residents and a host of modern trappings, such as a high-speed rail to connect sections of the 106-mile city. Saudi Arabian officials claim The Line will be otherwise devoid of roads, cars or emissions and will be powered strictly by clean energy (although details have not been released). Here are a few of most notable proposed features of The Line:

• vertically layered homes, offices, public parks and public schools.
• year-round climate control of all indoor and outdoor spaces.
• high-speed rail that will transport residents from end-to-end in 20 minutes.
• a five-minute walk to all amenities.
• accessibility to parks and natural elements within a two-minute walk.