Philip José Farmer's Riverworld

Riverworld is a 3D real-time strategy game based on Philip José Farmer's universe of books, where on an earthlike planet, with just one river flowing from pole to pole and back, all of mankind (a figure around 36 billions) is resurrected, from the first homo sapiens to the early 21st century population, as humanity was wiped out shorty after.

Playing as Richard Francis Burton, a British explorer from the 18th century (who has an uncanny resemblance to Welsh actor Timothy Dalton), the player decides to evolve the people from the prehistoric ages to the future. For that, he needs to build new houses to increase the population, conquer new territories (which will allow the player to both expand territory and progress into more advanced ages), meet other notable people from the human history and defend against other characters with the same goal in mind.