One of the most vexing aspects of traveling between mainland China and Hong Kong is the car travel: People in the former drive on the right side of the road; people in the latter drive on the left (a vestige of the British empire).
So to quell confusion at the border and, more importantly, to keep cars from smashing into each other, the Dutch firm NL Architects proposed a brilliant, simple solution, the Flipper bridge.
There’s even a cool little 3D concept video on YouTube. Just watch out for the music. Lethally bouncy: