4. The Cosmopolitan
Construction cost: $3.9 billion
Location: Las Vegas
Owner/Investor: The Blackstone Group
One of the latest additions to the Las Vegas Strip, The Cosmopolitan (or simple the Cosmo) is the most expensive privately funded building not just in Las Vegas, but in the entire United States. It was sold to the Blackstone Group in 2014 for $1.74 billion, which is a bargain considering that the construction alone cost $3.9 billion.
