Remember when "skyscraper" used to simply denote a very tall building, and the height of said building was enough to make you "ooh" and "aah"? While some of today's most notable proposed skyscrapers are notable just because they're tall, others are truly visionary to the extent of seeming like the belong in a sci-fi movie.
From a super tall tower in Saudi Arabia that's already under construction, to a Japanese behemoth that could save the country from climate change, you'll never look at a skyscraper the same after reading through this list (assembled in part using data from the Council on Tall Buildings and Urban Habitat).
Jeddah Tower, Saudi Arabia
Unlike many of the proposed skyscrapers on this list, the Jeddah Tower in Jeddah, Saudi Arabia is well under construction. When it opens in 2021, this residential building in Saudi Arabia's Red Sea port city will be the tallest building in the world, with a height of 3,281 feet (exactly one kilometer, the first skyscraper to cross that threshold) and 167 floors—four more than Dubai's Burj Khalifa, the planet's current tallest building.
Sky Mile Tower, Japan
Here's where it starts to get crazy—which if you've spent any time in Japan, not exactly known as a bastion of the typical, won't come as a huge surprise. If built, Sky Mile Tower will extend more than a mile (hence its name) into the air, topping out at 1,700 meters.
What's notable about this crazy proposed skyscraper, which will be completed sometime in the mid-2040s (if it's built at all) is its larger purpose.
For example, while it's not entirely crazy that Sky Mile Tower would be built on so-called "reclaimed" land (as the international airports for Nagoya and Osaka are), the building would act as a dam to hold back the rising waters of Tokyo Bay, and essentially to save Tokyo from Climate Change. (This is ironic, since the rising seas caused by Climate Change are one of the main deterrents used by opponents of using reclaimed land for construction.)
Additionally, the dam of Sky Mile Tower would contain desalination facilities that would provide drinking water to everyone who lived inside the building.
Wuhan Greenland Center, China
Mega-tall skyscrapers are nothing new for China—have you even been to, or even seen a picture of Shanghai? What's notable about the Greenland Center, slated to be completed sometime in 2019 if current estimates are correct, is that it illustrates a trend to which many in the West are oblivious: Chinese cities you've never heard of, in addition to being larger that most megalopolises in Europe and North America, will be home to the most impressive architecture of the 21st century. (The Greenland Center's home city of Wuhan, for its part, is a city of more than 10 million that sits along the Yangtze River, and has been inhabited for more than three millennia.)
Al Noor Tower, Morocco
Speaking of places you wouldn't expect to find crazy-tall buildings, would you believe that one of the world's wildest proposed skyscrapers is planned for Casablanca, Morocco? Setting aside the inextricable link between the city's name and the grandeur of early 20th-century cinema, this 1,772-foot tall skyscraper doesn't currently have a projected completion date but will be the tallest building on the African continent once it opens at some point in the future. Certainly it will be a sight to behold from the Hassan II Mosque, the current most-famous structure in Casablanca!
X-Seed 4000, Japan
Japan has a tendency to shock, both when you travel there and when you read articles about it. To be sure, there's a proposed Japanese skyscraper that's even crazier than the other one on this list.
The bad news is that the four-kilometer tall, Mt. Fuji-shaped X-Seed 4000 is never going to be built. The good (and, frankly, shocking) news is that a totally designed blueprint for the building exists, and has for more than two decades. So like, if you have a few quadrillion yen lying around, and a couple million workers to deploy, you could make history.
Of course, one important thing to know about this steel mountain (which would actually be bigger than the real Fuji), is that while a million people could theoretically live inside it, it was never intended to be taken seriously. Rather, the fully-designed plans were a tool to generate publicity for the Taisei Corporation, one of Japan's most famous construction firms.
The Dutch Mountain, Netherlands
Speaking of man-made mountains, Japan isn't the only country (maybe) going down that road. And while the Netherland's aptly-named Dutch Mountain (Die Berg Komt Er in Dutch) would've been only half the height of X-Seed 4000, it would've been more impressive, since the so-called "Low Countries" don't have mountains.
Like X-Seed 4000, the Dutch Mountain started as somewhat of a publicity stunt and grew into something more seriously, but while the futures of both these crazy proposed skyscrapers are uncertain, the fact that the ideas exist at all says something truly inspiring about human innovation.
Thai Boon Rong Commercial Towers, Cambodia
The Petronas Twin Towers rise above Kuala Lumpur like futuristic beacons, in spite of the fact that they're more than two decades old at this point. In a few years, though, the tallest twin towers in the world will still be located in Southeast Asia, but not in Malaysia—and probably not in the country you expected.
Mirroring the larger journey of Cambodia from a nation of poverty to one of the world's fastest-developing countries, the Thai Boon Rong Commercial Towers will rise 1,800 feet above the city of Phnom Penh (which itself has become almost unrecognizable over the past decade thanks to a building boom fueled by Chinese investment), changing not only the city's skyline, but the image the world has of the country. If everything proceeds according to schedule, the Thai Boon Rong Commercial Towers are expected to open in 2021.