In 2012, Tesla Inc. and Space Exploration Technologies Corp. Chief Executive Elon Musk published a proposal outlining a concept called the hyperloop, a futuristic transportation system to carry passengers through nearly airless tunnels at speeds reaching 700 mph. In renderings included in the proposal, faceless passengers are seen traveling in steely pods that look like something out of a science-fiction movie. Less than a decade later, Hyperloop Technologies Inc., doing business as Virgin Hyperloop, is testing a prototype of the system.

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