Robert Silverberg 
Regan’s Planet [EPUB ebook] 

In 1492, Colombus discovered America.In 1992 Claude Regan had to make it happen again!The US needed a shot in the arm as the twentieth century entered the last decade. And a World’s fair celebrating five hundred years of American civilisation might just do the trick.Regan was the trickiest, most ruthless promoter in the country. And the first thing he realised was that Earth wasn’t big enough to hold the kind of fair he wanted.So he built a new world!