Constructed in 1972, the Magic Roundabout in Swindon, England contains five small clockwise roundabouts located around a sixth counterclockwise roundabout.
While it's frequently criticized as one of the scariest junctions in the region, the Magic Roundabout is apparently a fantastically efficient design, thought I'd imagine it would take a few turns to get used to it. The Swindon Magic Roundabouts is one of several similar Magic Roundabouts in the UK. From 99% Invisible:
In such roundabouts, each peripheral circle facilitates car entries and exits from an associated feeder road. Experienced drivers can traverse the intersection in more direct and efficient ways, saving time. Less proficient motorists may choose to go with the flow, cycling around the edges until they reach their desired exit. For drivers going from one end to the other, a magic roundabout can enable traversals that are up to twice as fast as conventional roundabouts would allow.
(via @pickover)