Hudson Yards is a gigantic real estate project on New York City's western edge that will be the most expensive development in US history when it's completed in 2025.

At $25 billion, the project costs more than the size of the entire economy of Iceland… which is saying a lot given that Hudson Yards is only 28 acres… literally one millionth the size of Iceland.

According to the plan, in seven years (so they say) Hudson Yards will be a neighborhood of gleaming towers with high-end retail, fancy law firms and private equity shops, overpriced apartments, and ridiculous works of art like "the Vessel".

The Vessel is basically a giant woven staircase made from copper; it stands 15 stories, weighs 600 tons and has 2,500 climbable steps inside.

Did you know? You can receive all our actionable articles straight to your email inbox... Click here to signup for our Notes from the Field newsletter.

And this stairway to nowhere cost more than $150 million.

As the development company's founder Stephen Ross told Forbes, "[Hudson Yards is] not all about the money, really, it's about transforming something and what you leave behind."

Now, Warren Buffett has famously quipped that Rule #1 of investing is: Don't lose money. Rule #2: See Rule #1.

But I would add Rule #3 of investing: Anytime someone says "it's not about the money", you should run away. Quickly.

Now just think back to the last time a development was stealing headlines for being "the most expensive in US history."

It was 2004. In Las Vegas. And the development was MGM Mirage's City Center – a 67-acre playground on the Las Vegas Strip.

The development, and its 16.7 million square feet of casinos, retail, hotels and condos, was supposed to cost $4 billion. Construction started in 2006. City Center opened in late 2009, just in time for the Financial Crisis.

And the final bill for the Las Vegas City Center clocked in above $9 billion—a full $5 billion above budget.

(Remember, the Hudson Yards developer says their project will cost $25 billion… meaning the real cost will probably be north of $40 billion…)