We all know the phrase, “Go big or stay home.” The engineers behind the world’s largest construction projects are doing just that-and then some.

Being ahead of the curve is a position that rarely comes without a cost. When it comes to construction projects that break new ground or intend to improve upon already existing buildings or infrastructure, that cost comes in the form of dollars – lots and lots of dollars. Want the bragging rights to having the world’s longest bridge? Thirty-one miles of connectivity across China’s Pearl River Delta is expected to have a final price tag of $10.6 billion. One general rule of thumb that can be applied to these large-scale megaprojects: budgets get figured out in boardrooms. When it’s time to start getting dirty in the trenches, you might as well throw them out.

Back in 2008 California voters approved a plan for the state’s namesake High Speed Rail system, an 800-mile-long (1287 kilometer) stretch of track that will run from San Francisco to Los Angeles. Along the route 24 stations would be built and many of California’s major urban centers would be linked. Initially, estimates put the cost at $40 billion. Today, that number is on its way to $70 billion, with progress on the physical construction of the line being completed at a turtle’s pace. Yes, the irony has be duly noted that something intended to be so quick when it is finished is taking forever to build, but sometimes that curve we talked about earlier can be a doozy to get around.

Story by Jay Moon