When Biff Tannen
stole the DeLorean time machine
and went back to November 1955
, he gave his teenage-self a copy of the 21st century publication Gray's Sports Almanac
- a complete listing of sports scores from 1950 to 2000 - in order to change history so that he would be rich and powerful. Once Biff
had completed his goal, history - future history - changed and the timeline
skewed into a new tangent. When Marty McFly
, Doc Brown
, and Jennifer Parker
returned from 2015
they arrived not in 1985
but in an altered timeline referred to as 1985-A in Back to the Future II
Hill Valley 1985-A (called "Biff 1985" in the script and "Hell Valley" by some fans) is a much different place than the normal 1985. In the altered timeline Biff began gambling on sports in 1958, making his first million dollars soon after. In the 1970s he parlayed his winnings into a vast financial empire, BiffCo, and was one of the driving forces in toxic waste production. Many women sought after him, but in the end Biff married his high school sweetheart Lorraine Baines-McFly after the untimely death of her first husband George McFly.
By 1985-A Biff had taken over the Hill Valley Courthouse and converted it into his own flashy/tacky hotel/casino, Biff Tannen's Pleasure Palace. Near the entry of the complex is The Biff Tannen Museum, a visitor's complex that explains the history of "The Luckiest Man On Earth" all the way back to his great-great-grandfather, Buford "Mad Dog" Tannen. Smoking is required in the museum.
So obviously things turned out pretty well for Biff in 1985-A. But what of the other Back to the Future characters?
Thankfully the timeline was restored when Marty and Doc went back to 1955 and stole back the sports almanac. Once the book was burned, 1985 returned to normal.