In the standard Monopoly board game, which property group is colored dark blue?

In the standard Monopoly board game, Boardwalk and Park Place make up the dark-blue property group.

They are the final two purchasable street properties before the board returns to the GO corner. The pair is famous for having the highest purchase prices and some of the highest rents in the classic game.

Although Boardwalk is commonly discussed as the strongest individual property, a player must own both properties to control the complete color group and build houses or hotels under the standard rules.

A frequent mix-up is confusing the dark-blue group with the purple properties. In modern standard color naming, Park Place and Boardwalk are dark blue, while Oriental Avenue, Vermont Avenue, and Connecticut Avenue are light blue.