Here they are according to Popular Mechanics:
1: Kansai International Airport – Osaka, Japan
The airport is an artificial island 2.5 miles long and 1.6 miles wide—so large it’s visible from space.
2: Gibraltar Airport – Gibraltar
Sometimes it’s a road and sometimes it’s a runway.
3: Madeira International Airport – Maderia, Portugal
Engineers extended the runway to 9000 feet by building a girder bridge atop about 200 pillars.
4: Don Mueang International Airport – Bangkok, Thailand
Looks like any other midsize airport but between the two runways is an 18-hole golf course.
5: Ice Runway – Antarctica
The real challenge is making sure that the weight of the aircraft and cargo doesn’t break the ice.
6: Congonhas Airport – Sao Paulo, Brazil
“It becomes a challenge in terms of safety to just get the plane in there.”
7: Courchevel International Airport – Courchevel, France
“You take off downhill and you land going uphill with an 18.5 percent grade.”
8: Princess Juliana International Airport – Simpson Bay, Saint Maarten
Not many airports are flanked by oceanfront property with tourists standing underneath.
9: Svalbard AirportSvalbard – Norway
A cluster of islands sitting in the Arctic Ocean. It’s the world’s northernmost airport where tourists can book tickets.
10: Juancho Yrausquin Airport – Netherlands
The 1,300 foot runway is difficult even for Cessnas
11: Barra Airport – Barra, Scotland
When the tide comes in, the runway disappears.
12: Hong Kong International Airport Chek Lap Kok, Hong Kong
A 3.2 square mile island made by merging two smaller islands with reclaimed land.
13: Toncontin International Airport – Tegucigalpa, Honduras
The runway is 7000 feet long in a valley surrounded by mountains.
14: Qamdo Bangda AirportQamdo – Tibet
The world’s highest airport, more than 14,000 feet above sea level.
15: Dammam King Fahd International Airport – Dammam, Saudi Arabia
The largest airport in the world with over 300 square miles of desert.
16: Denver International Airport – Denver, Colorado
Has a 9200-panel solar farm and produces 3 million kilowatt-hours of electricity per year.
17: Macau International Airport – Macau
A set of highways links the runway with the small island of Taipa.
18: Copalis State Airport – Grays Harbor County, Washington
The runway is located between the mouth of the Copalis River and a barrier of rocks. It’s submerged every time the tide rolls in.