The world is full of inconceivably huge projects happening right under our noses.
Take the Hong Kong-Zhuhai-Macau Bridge, which will link three major Chinese cities in the country's quest to bring 42 million people together. Or Norway's plan to build the world's first fully-submerged floating tunnel to cut travel times between fjords in half.
Those efforts and many others illustrate how investing billions of dollars in enormous projects can collectively make the world a better place to live.
Here are some of the biggest projects the world has seen so far.
This gallery originally appeared as a Business Insider article.