The bridge in Amarante is great in its precise stonework detailing and overall proportions; the four flanking cylinders of stone are intersected with razor-sharp exactitude by the massive structural piers, triangular in plan.
But perhaps the most interesting feature of the bridge is that, given that it is meant to be seen reflecting, it wasn’t built as a perfect circle but as an oval, as you can see above. Only a contemporary designer would create it as such: the bridge is mainly seen from a steep angle (as in the top photo), and so by making its main arch it into a oval it actually looks more like a full circle than if it was indeed one.
The devil is in the detail, but sometimes in the bigger picture as well.
Ponte de São Gonçalo, Amarante, architect Carlos Amarante.