Mainz has buildings with restored half-timbered features and flamboyant Baroque and Rococo facades, and the largest Roman theater north of the Alps. Visit St Stephan's Church, which has beautiful blue stained glass windows from Marc Chagall. Mainz is Germany's wine capital and there's some award-winning wineries to visit outside the city, plus some great wine bars in the city center. The Riesling is top-notch for those white wine lovers.