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We show that two-dimensional photonic crystals can be designed to have dispersion relations with an extended ultra-flat cross-section, meaning that for a fixed wave vector component kx the frequency of a band is almost constant when the other wave vector component, ky, takes all possible values. These ultra-flat bands are the result of a non-trivial saddle point in the dispersion relation located in the interior of the Brillouin zone. Interesting consequences include 1D-like behavior, improved super-collimation, and enhanced density of states.