Billionaire Marc Lore is fleshing out his plan to build a utopian city called Telosa for 5 million people in the American desert — and he's not the only one with such ambitions.

Why it matters: There are about a dozen projects worldwide to create sustainable, hypermodern cities-from-scratch. While they may never come to fruition, the proposals themselves hint at what the city of the future might look like.

Driving the news: Telosa is set to be built on 150,000 acres in either Nevada, Utah or Arizona, and 50,000 "diverse" people will call it home by 2030, according to newly released details from Lore — a serial entrepreneur who sold Jet.com to Walmart for $3.3 billion and the parent company of Diapers.com to Amazon for $545 million.

In Lore's vision, vehicles will be electric and autonomous, and roads won't have curbs (which could hinder differently-abled people), or on-street parking.

How it'll work: A nonprofit called the Telosa Community Foundation will purchase the land to build the city — "land that is virtually worthless," as Lore put it.

Among those working to make Telosa happen: Preet Bharara, the former U.S. attorney for the Southern District of New York and a childhood friend of Lore's, and Bjarke Ingels, the prominent Danish architect whose firm is designing the city.

The big picture: Telosa, a name derived from the ancient Greek word meaning "highest purpose," is one of a growing number of dewy-eyed ambitions to build centrally planned and sustainable communities on a blank landscape — despite obvious impediments, like a lack of fresh water.

Other billionaires with city-building aspirations include Bill Gates, who wants to build a "smart city" called Belmont in the Arizona desert, and Elon Musk.

Reality check: Some of the claims being made by the utopian planners strain credulity — like Telosa's assertion that it'll eventually be a net exporter of water and energy.

The bottom line: The road to utopia is littered with shattered dreams.