I knew that Monopoly—the board game, not the economic concept—had evolved from a game designed to promote the ideas of the 19th-century radical Henry George. Now, thanks to a link in Christopher Ketcham's Harper's feature on the game's history, I've seen this site, featuring photos of the boards used in different versions of the Landlord's Game, as the Georgist version and its early successors were often known. Here's the original, drawn in 1903:
And here's an attractive edition from 1906:
Click through to the site for more boards and for close-up views. And take a look at Ketcham's story, too. The original Landlord's Game was patented, but despite that it evolved freely, with no authority stopping anyone from revising the rules or board to his or her taste. Ketcham explains how the game became the fiercely protected intellectual property of a single company.