Below are portfolios with photos of buildings from the 20th and 21st centuries.
Historic Shops in Porto
18 shops with historic fronts, most from between 1901 and 1942 and many in Arte Nova style
U-Bahn & S-Bahn Stations of Berlin
13 stations from between 1902 and 1913, two stations from the 1920s, one from the 1970s, two from the 1980s, and one from the 21st century
Buildings of the Amsterdam School in Amsterdam
35 public buildings and apartment blocks from between 1911 and 1932
Cubism & Art Deco in Prague
22 Cubist and 15 Art Deco structures, from 1912-1931
Art Deco & Bauhaus in Budapest
51 Modernist buildings from various parts of the city, from the end of Art Nouveau until World War II (1909-1942)
Berlin: Modern Classics
12 Modernist buildings or complexes (housing estates) from before World War II (1908-1936), including styles such as Neue Sachlichkeit, Streamline Moderne, and Brick Expressionism; 10 examples of post-war Modernism (1954-1987); 4 Deconstructivist buildings (1989-2012)
Tel Aviv White City
78 International Style (Bauhaus) buildings from the late-1920s to the late-1940s, with many undated buildings
Socialist Modernism in Belgrade
23 Socialist Modernist (mostly Brutalist) structures built between 1947 and 1989; from masterpieces to random residential blocks
Alvar Aalto in Helsinki
12 buildings designed by Aalto in Helsinki (1948-1976)
U-Bahn Stations of Munich
16 metro stations from between 1984 and 2010
grande flânerie 