When you walk in specific European cities you find that history is either very visible, or hidden just beneath the surface. In Rome and other places, every time someone digs they find ruins. As in the images below we see that the same is true, in this instance of Hvar, in Croatia. Imagine how many tens of thousands of people have walked along this street, without realising that there were mosaics.
What is nice in this instance, is that at least part of this ruin remains to be seen, protected by the street above. The buildings may have destroyed sections of this archeological site, but enough remains to allow people to take a glimpse into the past.