In an effort to reduce street traffic, London opened the Metropolitan Railway, the world’s first underground line, in 1863. Its origins can be found back more than two decades to the construction of the world’s first under-river tunnel beneath the Thames, which quickly became a popular pedestrian destination and major tourist attraction.

The London Underground was built on tracks dug slightly below ground and then covered over. However, as technology advanced and trains transitioned from steam to electric propulsion, the lines became deeper. The ground beneath Londoners’ feet now has an extensive network of tube lines that transport people around the city quickly, efficiently, and invisibly.

No one, not even Musk, has proposed burying all of the world’s roads. But what if we moved them all underground? Increasing urbanization, the unfair situation in society, and climate change raise important questions about how our global transportation system is changing, as well as make us consider where we truly want it to go.