Already a major international airport hub, Dubai is now planning to build the world’s biggest airport.

The city will likely spend $35.7 billion to develop a second airport which will spread across 35,000 acres and be able to accommodate 220 million passengers annually. The new multi-billion dollar investment will make the airport the biggest in the world when completed in an estimated 12 years.

Over the past five years, traffic at Dubai airport has increased 13 percent. It is expected that 83 million people will have passed through Dubai’s current airport this year. Last year that number was 78 million and it is expected that it will rise to 90 million next year, making it the busiest in the world. The airport already has the most international passengers passing through its terminals.

Al Maktoum International Airport will open in the south of the city, close to the site of the 2020 World Expo. By the year 2025, Dubai hopes to move Emirates, its flagship carrier, to the new airport. The two airports are expected to serve a combined 146 million passengers by that time.

The airport will be at the center of Dubai World Central, a 54-square mile development which will also include residences, offices and a golf course.