The Unterlinden Museum, housed in a 13th-century Dominican convent and a contemporary extension by Herzog & de Meuron, is the single must-see in Colmar. The collection is built around the Issenheim Altarpiece, Matthias Grünewald's blistering early-16th-century masterpiece of crucifixion, resurrection and disease, displayed in the convent's former church.
Other highlights include a strong group of medieval sculpture and panel paintings, a Roman archaeology section in the basement, and a small modern wing with works by Picasso, Soulages and Bonnard. The Christmas-season setting, when the cloister fills with carved nativities, is particularly atmospheric. Allow at least two hours. Tickets are not cheap by French museum standards but cover both the original and modern buildings.