Kohn Pedersen Fox
A recent proposal highlights plans for a building called the "Sky Mile Tower", which would rise a mile above Tokyo Bay.
At almost double the size of the world's current tallest building, Dubai's Burj Khalifa, the skyscraper would be the world's new tallest if built.
The skyscraper is part of a larger proposal by Kohn Pedersen Fox Associates (KPF) and Leslie E. Robertson Associates called "Next Tokyo 2045", which outlines ways in which an eco-friendly district could be built to combat rising sea levels in Tokyo Bay.
No funding has been announced, but if it is built, the structure will house sky decks that rise as high as 420 stories.
Scroll down to see what the project would look like if it comes to fruition.