Perhaps the first drawing one learns in early elementary-school art education is of the rudimentary "triangle on top of a square" house. The second technique may well be coloring within the lines. On the other end of the education spectrum, one of the first professional drawings one learns in architecture school is, similarly, of the A-frame house. Architectural rendering (an advanced "coloring within the lines," if you will), on the other hand, is a painstaking exercise that that takes decades of experience to master.
One architect, however, is bringing both worlds together, by coloring in between the lines of architectural renderings and photos, thus turning landmark buildings into color-negative line drawings. Gran Fachada (Grand Façade, in English) is the result of hours of permanent-marker coloring by Madrid-based architect and designer, Marlon de Azambuja.
Above, the Hirshhorn gets de Azambuja's line-drawing treatment, and it gives us carpal tunnel just thinking about how much time went into these illustrations. Below, more images from Gran Fachada:
Recognize these landmarks? Above includes the Pompidou, Caixa Forum, Circulo de Bellas Artes, MASP, Musac, Wiels, MACBA, the Whitney, and Tate, respectively. If you're not architecturally-versed, head over to Marlon de Azambuja's website to get yourself even more acquainted.
h/t Faith Is Torment