The wavy bridge of La Barra is a local attraction, because given enough speed, it feels like being in a roller coaster when you pass over it. The bridge was created by an Uruguayan engineer called Leonel Viera. He was the first to use this particular construction method, in which the supporting cables actually pas through the bridge itself and are embedded in the concrete. This type of construction is called a stressed ribbon bridge.
The bridge on the right was the first one to be built. Not so long ago, a second, identical, bridge was added. If you get to ride this bridge: the one on the left (so driving from La Barra to Punta del Este) is the most fluid roller coaster.
More pictures of La Barra can be seen here.