Azulejos are tiles used to decorate facades and interiors, sometimes strictly ornamental (like: in an Islamic tradition), sometimes forming giant allegoric pictures. There’s a whole museum dedicated to them and their history, the Museu Nacional do Azulejo, one more museum that I haven’t seen and probably should have. Again: next time.
But then, it’s not that I have not seen any azulejos in Lisbon. The whole city is full of them. You find them on plain houses like in this image, but also in churches, and we will get to some allegoric pictures in a few weeks 🙂