A starfish's usual habitat is the bottom of the seabed, but this one takes up more than 700,000 square meters (173 acres) of land 45 kilometers (nearly 30 miles) south of the Chinese capital. Opened by President Xi Jinping on Wednesday, Beijing Daxing International Airport is expected to become the world's biggest airport due to the continued economic rise of the Asian powerhouse.

Designed by the late Iraqi-British architect Zahara Hadid, who died in 2016, the airport took less than 5 years to construct and cost 120 billion yuan ($17 billion, €15.4 billion). The airport is expected to reach full capacity, some 72 million passengers a year, in 2040.

One of the largest single-structure airport terminals in the world, Beijing Daxing stands out for its flowing, curved lines and use of natural light that filters down to the lowest levels of the building through openings on the roof.

The size of the terminal may put off those travelers with mobility issues, who presume that the huge structure will mean longer walking times after check-in. However, the airport's management has promised a distance of no more than 600 meters (656 yards) between the security checkpoints and aircraft, which would take about 8 minutes to walk.

The unveiling of the new mega-airport took place just days before China celebrates 70 years of Communist Party rule. Air transport is booming as living standards increase along with peoples' desire to travel. The country is expected to surpass the US to become the world's biggest aviation market by the mid-2020s, according to the International Air Transport Association.

China's leaders promise that Daxing would be one of the most technologically advanced airports in the world. Huawei will provide a 5G smart travel service that will allow the integration of advanced communications for travelers, airlines and the airport's management. Facial recognition will be used not only for check-in and security but also for flight attendants to help passengers to their seats.

One small opening hitch happened when the maiden commercial flight from Beijing Daxing International Airport — an A380 superjumbo heading to the southern city of Guangzhou — was delayed by nearly 30 minutes. Although several foreign and domestic airlines plan to move their operations to the new airport, most carriers will likely wait for opening glitches to be ironed out.

When it comes to passenger numbers, no airport can measure up to the one in Atlanta. Almost 104 million people passed through Hartsfield-Jackson air-traffic hub in 2017, according to data provided by airport association ACI. No other airport has managed to break 100 million. This makes Hartsfield-Jackson number one on our list.

China has its own favorite: Beijing Capital International Airport ranks second in the number of passengers, welcoming 95.8 million people in 2017. The air-traffic infrastructure was built up ahead of the 2008 Olympic Games. UK star architect Norman Foster designed a new, sprawling terminal for the event.

In 2017, Dubai's airport welcomed over 88 million passengers. Almost all of them were non-Arabs — as many as 87.72 million. Many of them apparently appreciate Dubai International for its almost legendary reputation for shopping.

Alas, the Japanese capital is not in the top three, but its airport still boasts 85.4 million visitors per year, enough for a solid fourth place in our ranking.

If you go on vacation to California, chances are you will land at Los Angeles International Airport, better known as the LAX in America. The flow of passengers does not quite measure up to the Atlanta airport, but it still had over 85.5 million visitors last year.

Even in Chicago, there is no rest from fans for German football star Bastian Schweinsteiger. The former Bayern Munich and Manchester United midfielder now plays for Chicago Fire, and frequently flies through O'Hare. Schweinsteiger is only one of 79.81 million passengers who go through the Chicago hub, which is named after an American WWII pilot.

London boasts three airports, the largest and most well known of which is Heathrow. It services just over 78 million passengers per year. And it manages all that with just two runways.

You don't have to be in a plane to sneak a good look at Hong Kong's competitor, called Chek Lap Kok Airport locally. The compound is similarly impressive from a cable car as it may have been for the 72.67 million passengers who travelled through it in 2017. Hong Kong, or "fragrant harbor" in English, is built on reclaimed land on the island of Chek Lap Kok in the South China Sea.

Safety first! One of Shanghai's two airports ranks just behind Hong Kong's. Pudong International Airport served 70 million passengers in 2017. This marks a slight drop from the year before, but cargo flights picked up by over 11 percent, according to ACI.

The Paris airport named after President de Gaulle, also known as Roissy airport, comes in at number 10 on our list of busiest air-traffic hubs. Last year, it welcomed 69.47 million passengers. But those figures are not everything in an airport ranking; there are also parameters such as the amount of goods transported, the size, the number of terminals and many more.

And then there is the amount of time it takes to actually build an airport. In that respect, the Germans might well be No. 1. Perhaps it's simply a question of definition: The nine years that have so far passed since construction began could be seen as evidence of thoroughness.