Many of such colorful boats, as you see in the photo, are docked along the Douro River in Porto. Most of these boats are now just touristic attractions, but back in the day, the Port wine was transported with them. Aside from these small boats owned mostly by Porto wine producers, there are many others in the harbor, which are used now for visiting the Douro valley nearby Porto.
More about this image here:
https://sumfinity.com/hdr-photos/portugal/porto/spring-time/
