Years ago, on a travel TV show, I saw a visit to the underground of the slave market of Salvador, and I put it on my mental 'to-do' list. It impressed me enough that I didn't forget, and H and I went to Salvador.... Only to discover that the underground of the slave market has been closed, and the upstairs turned into yet another souvenir market (boring!).
Well, that was a disappointment! But there were other things to see, and the tourist information office pointed us in the right direction.
NB: Salvador's tourist information office at the top of the cliff elevator is the most helpful and friendly I've found in Brazil.
What we discovered is a Unesco listed historical centre with, apparently, the most baroque architecture that you'll find outside of Europe. But, for me, it was better than Europe.
They call this area of Salvador 'Pelourinho' (or Pelo for short). I loved the Pelo because not only were the buildings beautiful in their Baroque architecture, but they were colourful too. There was pink beside green beside blue, etc. And, with colourful people (Brazilians seem to love a bit of colour) it all felt so, well... Brazilian!
I recommend visiting Brazil's Salvador. It's beautiful. (photos attached)
Overlander Note: we beach camped on Itaparica island, then used the paid parking at the ferry terminal to leave Blac in a bit of security for the day, then travelled across to Salvador and back as foot passengers.