A walk through the bright, handsome galleries of one of Germany’s outstanding art museums provides a head-spinning look at Western masterpieces. For many Hamburgers, pride of place in the two buildings belongs to the Bertram altarpiece, painted for the St. Petri Church in 1379. The 24 scenes depict the history of humankind as told in the Bible, from creation to the flight into Egypt. Look for some sardonic touches, like the little fox chewing the neck of the lamb next to it, a sad comment perhaps on the fate of the meek. Continue through the Canalettos, Rembrandts, Holbeins, and other old masters to German Romanticism. Among these works is Caspar David Friedrich’s “The Wall of Mist,” the object of a much publicized heist in which the painitng was stolen from a train and later returned. The new wing by O. M. Ungers houses the Galerie der Gegenwart, Art of the Present, with an impressive collection of canvases by Picasso, Warhol, Beuys, Munch, Kandinsky, Klee, Hockney, and many other leading contemporary artists currently making waves in the art world, among them installation artist Rebecca Horn, photorealist Gerhardt Richter, and conceptualist Jenny Holzer. A large showing of German Expressionism is a credit to the museum’s effort to rebuild a collection of “degenerate” art banned and often destroyed by the Nazis.