On my visit to Mainz (with a kind host), we saw some of the buildings in the postcards, for example, the tower of picture 18 (Holzturm). During the second world war, Mainz was almost completely destroyed. Thus, many of these former, schönsten views of the city look much different today. The buildings lining the Marketplace (Nr. 7) were reconstructed and look very nice. Also, the cupola of the Christuskirche (Nr. 17) is again a city landmark. The Dom (the Cathedral) is one of the three Rhine-oriented romanischen Kaiserdomen (vis Diözese Mainz, Worms and Speyer) and it looks almost the same as it did at the turn of the century. See and search for Doms here.