The Kansai International Airport has a very unusual location: the sea.
An artificial island was constructed specially for the airport.
It sees a whopping 25 million passengers travel through it each year.
But there’s a chance the airport will disappear completely in the next few years.
In the 1960s, Japan needed to build a new international airport but couldn’t find a spot that wouldn’t garner noise complaints from residents.
So the country looked for an area where neighbours wouldn’t be a problem: the sea.
Engineers built an artificial island called Kankūjima off the coast of Osaka.
It’s 2.5 miles long and 1.5 miles wide and took 10,000 workers and 10 million man-hours to build.
The island is only accessible by the Sky Gate Bridge and has two terminals on it.
Terminal 1 is 1.1 miles long and held the record for the world’s longest terminal for a number of years.
During its construction, sceptics pointed out that such a feat was dangerous in an area so prone to natural disasters.
Since then, the airport has survived a number of catastrophic earthquakes and typhoons impressively unscathed.
But it faces a serious threat from a disaster of its own making.
The weight of the island and the buildings are compressing the seabed silts they’re built on.
This means the island is slowly but surely sinking.
It sunk over 26 feet in just five years, which is 25% more than what the engineers had predicted.
Some experts say it’s got another 100 years before it totally disappears, while others say it’s closer to 25 years.
The country spent an eye-watering $20 billion on construction, a lot of which has gone towards solving the sinking issue.
That’s a lot of money to potentially throw into the sea.