A simple, but unusual and elegant design: a bridge in the city of Leeuwarden in the Netherlands uses two arms to swing a section of road in and out of place. It's called the "Slauerhoffbrug" and was built in 2000.
Image Gallery and Aerial View via The Presurfer | Photo: Frozenly
It looks interesting but over the top and kinda ugly too, as a native Rotterdammer i wouldn't like to have that in front of my house.
http://maps.google.nl/maps?f=q&source=s_q&hl=nl&geocode=&q=Pieter+de+Hoochweg,+Rotterdam&sll=47.829956,-1.670919&sspn=0.001264,0.002929&ie=UTF8&hq=&hnear=Pieter+de+Hoochweg,+Rotterdam,+Zuid-Holland&ll=51.908511,4.458593&spn=0.001162,0.002929&t=h&z=19
Like the elliptical arch. For centuries no one thought of it - but once someone did it was obvious. If you could just say to an early medieval builder "elliptical arch" he'd like as not immediately grasp what you meant - all the pieces were there but no one made the leap.
Early arches were semicircular. Later arches introduced pointed arches made from two circle segments leant against each other to give long tall windows. Finally, for bridges, someone realised that you don't have to have a semicircular arch - which makes the bridge too high for people to easily cross without expensive ramps leading up to it, but that you can flatten the arch to leap a far wider span without the height penalty.
Most stonework river bridges are elliptical arches.