A church in the plateresque renaissance style with an ogee apse. It's a three-naved building with one single tower, a fine example of late Romanesque art. It began to be built by the stonemason from Biscaia and Castile Tomé de Tolosa (1488) and was carried forth by Pero Galego.
Inside it's possible to admire 17th and 18th century tiles as well as the maple wood ceiling in Mudejar style.
While walking along the river, if you look at the opposite direction - that is, the village - you will see the castle's wall. It is another landmark in Caminha. As many villages and towns spread around Portugal, these places used to have a castle for defence purposes. Nowadays, there are lots of houses built around these walls.
Any visit to Caminha is not completed until you discover the river (River Minho). Take a long walk along the river and enjoy the magnificent views it provides. If possible, walk during sunset and you will never forget it. The hill across the river is Spain. In the river you might notice several coloured boats, which are used for fishing purposes.
After looking at these reference buildings, take a quiet stroll around the cobbled and narrow streets of Caminha. You will notice some Portuguese architecture, typical from the north - robust looking houses, yet charming, that have been built over a century ago. Back then, houses were made of solid stone and in some of them you can notice the family's coat of arms engraved on stone. Some of them have also beautiful wooden doors or some elaborate iron gates.
As I mentioned previously, the square it's a good starting point for some walking around and sightseeing:
> Passos do Concelho (City Hall)
> Solar dos Pitas (a 15th century building)
> Torre do Relógio (Clock Tower, 15th century)
All the mentioned buildings are around the square so you won't miss them.
This central square is one of the town's central points. Everything seems to happen "from" here and town lives around the square. It is the perfect place to start exploring around (walking) and also to finish, since you can sit on one of the several open-air cafes and relax while enjoying some drink or something to eat. And be sure to take some time to observe locals going by on their daily activities. Caminha is not that touristy so most people you can see around you are either locals or Portuguese that come and spend some weekend here.