With the world population expected to hit 9.6 billion people by 2050, architects and developers are looking for innovative ways to answer to growing housing demand as available space to build on dwindles.

Now, there are plans for cities and residences that answer density issues by building nearly 1,000 feet into the ground, cities that float on water, and an entirely man-made archipelago built across 300 islands designed to look like a map of the world.

Collected from Lamudi, a global property database that focuses on emerging markets, and the archives of our sister site Multifamily Executive, here are eight fantastical cities of the future that could change the way we live and build by 2050.

Khazar Islands, Azerbaijan

This island development south of Baku will consist of 41 islands spanning over 12 square miles in the Caspian Sea. It will house over one million residents, and have 150 schools, 50 hospitals, parks, malls, universities, and Formula 1 quality racetrack around the island’s perimeter. The island will be home to the Azerbaijan Tower, which will be the world’s tallest building at 3445 feet, 728 feet taller than the Burj Khalifa. The project is expected to be completed in 2022.

Photo courtesy of LAMUDI The World Islands

The World Islands, Dubai, United Arab Emirates

The plan for The World Islands involves constructing a man-made archipelago across across 300 islands designed to look like a map of the world. It will feature luxurious half-submerged floating homes with underwater master bedrooms.

Photo courtesy of LAMUDI

Masdar City, Abu Dhabi

Promising to be the world’s first zero carbon zero waste city, Madsar City will rely on solar power and other renewable energy sources for power. The building keeps temperatures at a regulated 60 degrees Fahrenheit thanks to a 150-foot high wind tower that sucks air from above and blows it back to cool the streets. To cut down on emissions, the only transportation allowed within the confines will be provided by driver-less electric cars.

Photo courtesy of LAMUDI

Earth-scraper, Mexico

This 65-story building won’t go up, but down. The upside-down pyramid-shaped “earth-scraper” will plunge almost 1,000 feet into the ground. The city will be able to fit 300,000 people and will feature housing, retail, 10 floors of office space. An 800-square-foot glass roof will allow natural sunlight to flow in.

Crystal Laputa Floating City, Chengdu, China

Three towers and a mid-rise building will comprise this development that floats over a man-made lake in China. On the third level, the structures will be connected by an expansive green space that stretches over a street and features recreational areas and running trails.

Photo courtesy of LAMUDI

Ocean Spiral, Japan

Shimizu Corporation designed a floating globe with a 1,600 foot diameter that will house hotels, residential spaces, and commercial buildings. The modern day Atlantis will also have a 9-mile spiral structure that extends to the sea floor. An “earth factory” would mine the sea bed for minerals and metals and produce methane and carbon dioxide by using micro-organisms.

Vertical City, to-be-determined location in the Middle East

Italian firm Luca Curci Architects seeks to redefine the role of a contemporary skyscraper with this 180-story, 2,460-foot-tall modular, vertical city that will rise from the ocean. The energy-independent tower will house 25,000 residents and be constructed with 10 overlapping modular layers that sustain each floor and will be powered by a membrane of photovoltaic glass that will deliver electricity to the entire building. An underwater bridge connects pedestrians and cars on the mainland with the submerged, circular basement on which the Vertical City is set.

City Sand Tower, Morocco

The 1,450-foot tall tower, designed by French architectural firms OXO Architectes and Nicolas Laisné Associés, will power itself in the Sahara desert. The rock-like 8.4 million-square-foot building would house offices, 600 residences, a hotel, shopping center, sport facilities, a panoramic restaurant and bar, a spa, a museum and an observatory. An inner-tower covered in vegetation will act as a vertical farm for food sustainability.