This mega palace on fifth avenue belong to Andrew Carnegie and his wife Louise. Andrew Carnegie was called the "Steel King" and owned Carnegie Steel. When he retired he sold Carnegie Steel to J. P. Morgan for $400 million and built a beautiful estate in Scotland on 40,000 acres called "Skibo Castle". He also wanted a New York City residence so he could manage his charity ventures. Andrew planned to give away all of the $400 million, except for $10 million for his family.