One of the little lanes which runs down the hill from near the hospital to the riverside. This isn't really a backstreet, but then it is often hard to tell in Porto what constitutes a street, an alley or a back lane. It's also often hard to figure out whether you may have stumbled into the dodgiest neighbourhood in town or some up-and-coming boho area. To be honest I think this particular street is pretty safe and is a bit of a mix.
At the bottom you can make out the Capela de Nossa Senhora da Esperança which is attached to the much grander Igreja de São João Novo. There's quite a fancy square just to the left, albeit a little bit faded.