7 Out Of 10 People Will Live In Cities By 2050

Goodbye, little house on the prairie.

As people flock to urban centers, engineers will need to figure out how to accommodate them. In 2006, New York’s Metropolitan Transportation Authority started digging a train tunnel beneath Manhattan to connect the Long Island Rail Road, the nation’s second busiest commuter train system, to Grand Central Terminal. Where the two systems will meet, at a new station 14 stories below ground, two 85-foot-tall caverns are currently under construction.

This article originally appeared in the February 2014 issue of Popular Science.