The Cathedral (Katedrála) is an abstract painting created by Czech artist František Kupka in 1912–13. The medium is oil on canvas, and the painting’s dimensions are 180 × 150 cm. The painting is a part of the permanent Jan and Meda Mládek collection of Museum Kampa in Prague, Czech Republic. This painting is one of a series of abstract works that Kupka termed Vertical and Diagonal Planes. Vertical lines, running the entire length of the canvas are intersected by diagonal lines to form rectilinear shapes of various sizes. The diagonal lines run from the top left to the bottom right and from the top right to the bottom left of the painting. These rectilinear shapes are composed of blocks of black, white, and a range of blue, red, purple, gray, and brown color. The large black space between t