7 multi-billion dollar mega projects that are remaking the world's greatest cities

All over the world, real estate developers and local governments are trying to find ways to cram people into denser and denser cities.

In many cases, they're relying on mega projects, ranging from $4 to $40 billion dollars in cost, that are reconfiguring the layouts of places like New York, Sydney, and Tokyo.

"It's a migration of workers and companies to cities, and a flood of capital into marquee addresses," MIT real estate professor Steve Weikal tells Tech Insider.

Here are seven of the most mega of mega projects, according to Weikal.