A crucial step towards building the next tallest building on Earth is underway: Engineers on the Kingdom Tower, a proposed 3,280 foot tower in Jeddah, Saudi Arabia, are beginning tests to figure out how to pump wet concrete more than half a mile into the sky.

SEATTLE — A secret subterranean heart, tinged with mystery and myth, beats beneath the streets in many of the world’s great cities. Tourists seek out the catacombs of Rome, the sewers of Paris and the subway tunnels of New York. Some people believe a den of interstellar aliens lurks beneath Denver International Airport.

1000 ton bridge over the country's busiest motorway being demolished overnight, a good display of coordinated action where every minute counts and the job has to be completed

I love the newly city approved Beach & Howe Tower in Vancouver, Canada, a gorgeous 54-story apartment building designed by Danish architects Bjarke Ingels Group. It gets extremely thin on its base to avoid a passing highway. From some angles it looks like it may fall to its side. Enjoy all the beautiful pictures.

The Capitol Dome is to be surrounded in scaffolding as it undergoes a renovation.

The final piece of an intricate puzzle will be slipped into place this weekend. The I-84 corridor that connects New York State to Connecticut is getting an upgraded bridge, and the way they're doing it saves money, limits closures, and could revolutionize the way America remakes its crumbling infrastructure.

Blundering Chinese officials were forced to cut a motorway in half to go around a block of flats after they accidentally erected the building in its proposed path then realized it would cost too much to relocate the tenants. Construction workers had to squeeze the eight-lane highway into four and subsequently left furious residents stuck in the middle of a busy road.

At what point does a building become a city? At 1.7 million square meters, the New Century Global Center lands somewhere between the two.