The largest construction projects in the world range from canals, airports, subways, utility projects, modern cities and industrial complexes. Other projects include entertainment parks and the International Space Station. Below is a complete compilation of the top 15 largest construction projects in the world;
NEOM City.
NEOM, meaning ‘new future’, is a futuristic city under construction in Saudi Arabia. Dubbed as a ‘living laboratory’, it will be comprised of cities, towns, ports, and enterprise areas. It is set to accommodate over one million people from all parts of the world by 2030. The scheme has a total estimated cost of around $500 billion (£371bn).
The Gulf Railway
The Gulf Railway will link all six member states of the Gulf Cooperation Council (GCC) in the Persian Gulf, stretching on a total length of 1,353 miles (2,177km). earlier scheduled to complete in 2018, the colossal $250 billion (£185bn) scheme was halted as a result of low oil prices and disagreements between the member states.
The project’s first phase– the line from Saudi Arabi through the United Arab Emirates and Oman – will complete in 2023. Phase 2, which will connect up Saudi Arabia, Kuwait, and Bahrain is also set to complete by 2025.
Silk City
Silk City is a 96.5 square mile (250 square km) project set to home to the world’s tallest towers. The Burj Mubarak Al Kabir tower will rise 1,001m (3,282 feet) high, with its height keenly chosen as a nod to One Thousand and One Nights.
The city will include a new airport, hotels, nature reserve, spas, and parks. It is expected to complete after around 25 years.
King Abdullah Economic City
The city is named after the late King Abdullah and is developed with a focus on education, business, and property. It is anticipated that the glittering new Saudi city will be bigger than Washington.
With an area of 67 square miles (173 square km), the project of the futuristic metropolis was revealed in 2005 and is currently planned to complete in 2029. It’s total cost is around watering $100 billion (£74bn).
Delhi-Mumbai Industrial Corridor
This is India’s most visionary construction scheme to-date and will comprise of five power projects, eight smart cities, 24 investment regions, and two airports, among other components.
It was started as Indian and Japanese governments joint project in 2006. The four phases of the  $100 billion (£74bn) development are all  currently set to be completed in 2037.
Al Maktoum International Airport, Dubai
Stretching more than 21 square miles, Dubai’s Al Maktoum International Airport is the largest construction project in the world. Upon its completion, the airport will handle 200 wide-body aircraft at a time. The airport’s second expansion phase alone has an estimated cost of more than $32 billion. Originally scheduled for completion in 2018, the latest expansion phase has been delayed, with no definite completion date.
Jubail II, Saudi Arabia
Jabail II is an $11 billion expansion project for the 22-year-long industrial city project which started in 2014. When completed, the project will comprise an 800,000-cubic-meter desalination plant, at least 100 industrial plants, an oil refinery producing at least 350,000 barrels per day, and miles of railways, roads, and highways. The entire project is expected to be completed in 2024.
Dubailand, Dubai
The Dubailand complex will bring together three Walt Disney Worlds in a single location and is one of the largest construction projects in the world. The $64 billion project sits on a 278 sq. km land and will have six parts; theme parks, sports venues, eco-tourism, health facilities, science attractions, and hotels. The complex will also house the world’s largest hotel, with 6,500 rooms, and a 10-million-sq.ft mall. The project is scheduled for completion in 2025.
International Space Station, Space
The International Space Station orbits the earth once every 92 minutes. The Station was developed by a partnership of 15 countries and five space agencies. The project has a construction cost of more than $60 billion. The space station is still undergoing several developments and expansions that could drive its final cost to more than $1 trillion.
South-North Water Transfer Project, China
Northern China is home to almost 50% of the country’s population but this population is supported by only 20% of China’s water resources. As a remedial solution, China is constructing three huge canals of more than 600 miles each that will supply water to the north from the three largest rivers in the country. The project is expected to be completed in 48 years and will supply 44.8 billion cubic meters of water every year.
London Crossrail Project
The London Crossrail project is the first underground train system in the world. The project is making progress and hopes to add 26 miles of tunnel. The railway line will connect 40 stations. The project is expected to cost $23 billion and will be completed in phases.
High-Speed Railway, California
Construction of California’s high-speed train started in 2015 and is expected to be complete by 2029. The railway line will connect eight of the 10 largest cities in California. Construction will be conducted in two phases with the first phase connecting Los Angeles to San Francisco while the second phase will extend to San Diego and Sacramento. The train will be 100-percent electric and will be powered entirely by renewable energy and capable of speeds up to 200 miles per hour.
Chuo Shinkansen, Japan
Chuo Shinkansen is Japan’s newest high-speed rail and is officially called Linear Chuo Shinkansen. The train is expected to travel at speeds up to 505 kilometers per hour and will take travelers from Tokyo to Nagoya—286 kilometers—in 40 minutes. The project is expected to be complete by 2027. About 86 percent of the Tokyo-Nagoya line will be underground, requiring extensive tunnel construction.
Beijing Airport, China
Upon completion, Beijing International Airport is expected to surpass Dubai’s Al Maktoum International Airport in cost, total square miles, and passenger and plane capacity. The first phase of the project was completed in 2008 and further expansion is expected to be complete by 2025.
Great Man-Made River Project, Libya
Libya has been constructing the “Great Man-Made River” (GMR) project since 1985. It will be the world’s largest irrigation project and will irrigate more than 350,000 acres of arable land and will substantially increase available drinking water in most of Libya’s urban centers. The river will draw its water from the underground Nubian Sandstone Aquifer System. The project is set to be completed in 2030.
Grand Paris Express
The Grand Paris Express is an ambitious infrastructure project in the Paris metropolitan area, France. It aims to expand and improve the existing public transportation network by constructing new metro lines, extending existing lines, and creating new stations. The project was initiated to address the growing population, urbanization, and transportation needs of the region.
The project involves the construction of four new fully automated metro lines, namely Lines 15, 16, 17, and 18. These lines will significantly expand the metro network and improve connectivity between the suburbs and the city center.
The project also includes extending the existing metro lines to reach new areas and improve accessibility. Several existing lines, such as Lines 11 and 14, will be extended to connect with the new lines, creating a more integrated and comprehensive network.
