The most expensive large-scale projects in the world range from airports to entire city districts.
While some changed a lot of lives for the better, such as public transit systems, others are just billion-dollar eyesores, like the never-completed Dubailand.
We’ eve ranked the top 15 according to their inflation-adjusted cost using this calculator.
Inflation-adjusted cost: $12.7 billion.
Cost in 2001: $10.3 billion
New York's JFK airport is among the busiest in the world. The airport's comprehensive expansion a decade ago included building new terminals and constructing an 8-mile-long AirTrain to make it public transit-friendly.
Inflation-adjusted cost: $17.9 billion
Cost in 2007: $17 billion
This subway line on the east side of Manhattan has been in the works for 75 years but delayed because of funding problems. Developers broke ground on the project in 2007.
Source: New York Magazine
Inflation-adjusted cost: $22.4 billion
Cost in 1994: $15.4 billion
This amazing underground tunnel takes high-speed railways 31.4 miles underneath the English Tunnel into France. In 1996, it was named one of the Seven Wonders of The Modern World.
Source: The Los Angeles Times
Inflation-adjusted cost: $23 billion
Cost in 2005: $22 billion
The Airbus A380 is the world's largest passenger airline, designed in an attempt to one-up the company's archrival, Boeing. It flew for the first time in 2005. One plane retails at $300 million.
Inflation-adjusted cost: $23 billion
Cost in 2000: $18.4 billion
The Toei Oedo subway line was Tokyo's first linear motor metro line, meaning it could carry smaller passenger cars. It took nearly 10 years to build and is the world's most expensive subway.
Inflation-adjusted cost: $23.1 billion
Cost in 2007: $22 billion
The Big Dig tunnel in Boston rerouted Interstate 90, the chief highway, through the heart of the city. It was completed 10 years late and because of design flaws and leaks the builder had to pay $407 million in restitution. It won't be paid off until 2038.
Sources: The Boston Globe
Inflation-adjusted cost: $26.1 billion
Cost in 2008: $25.8 billion
This railway connects two of China's biggest cities is the longest high-speed railway ever to be constructed in a single project. Trains go upward of 200 miles per hour, meaning you can go from one city to another in 4 hours, 48 minutes.
Source: The Telegraph
Inflation-adjusted cost: $27 billion
Cost in 1998: $20 billion
Hong Kong's main airport is one of the busiest in the world and employs 60,000 people. In 2011, 53,314,213 passengers went through the airport.
Source: Airports Council International
Inflation-adjusted cost: $29 billion
Cost in 1994: $20 billion
Kansai International Airport operates out of the Osaka Bay in Japan. The airport is actually located on a man-made island that engineers designed to withstand the earthquakes and typhoons common to the region.
Source: The New York TImes
Estimated Cost: $40 billion
The Songdo International Business District is a planned Central Business District in Seoul, South Korea that's being built on reclaimed land. It will contain a replica of Central Park. The Business District will be completed by 2020.
Source: The Independent.
Inflation-adjusted cost: $76 billion
Cost in 2003: $64 billion
Dubailand was launched in 2003 and was supposed to include 250 projects including a Disney theme park, an IMAX theatre, a Six Flags park and a shopping mall. The developers collected $55 billion in private funding for the project. But construction was halted in because of the country's financial crisis in 2008 and hasn't resumed.
Estimated Cost: $98.5 billion
The California High-Speed Rail is a project that will connect cities all over the state from Sacremento to Los Angeles by public transit. Construction will begin in September of this year.
Source: California High-Speed Rail Authority.
Inflation-adjusted cost: $95 billion
Cost in 2005: $86 billion
King Abdullah economic city is supposed to solidify Saudi Arabia's reputation as a business centre. In all, the project will include six cities and will house four million people. The estimated completion date is 2020.
Cost to date: $150 billion.
The International Space Station orbits Earth and is used as a lab to conduct experiments in physics, biology and astronomy. Astronauts from around the world have lived there for 11 years.
Sources: The Space Review
Inflation-adjusted cost: $459 billion.
Cost in 2006: $425 billion
The Interstate Highway System was started in 1955 to make the whole U.S. accessible through highways. It includes 46,876 miles and its estimated that one-third of all miles driven are on the system.
NOW WATCH: Briefing videos
Business Insider Emails & Alerts
Site highlights each day to your inbox.