St. Martin's, often called the cathedral of Colmar even though it never held the title, dominates the central square. The 13th- and 14th-century Gothic structure mixes pink and yellow sandstone, giving it a warm, almost-rosy colour in low sun. The carved tympanum over the south porch — the Last Judgement, with its devils dragging the damned away — is worth a careful look.
Inside, the soaring nave is mostly bare, the result of revolutionary stripping in the 1790s. A handful of treasures survive: a 14th-century crucifix above the high altar, fragments of medieval stained glass in the choir, and a magnificent Silbermann organ from 1755 (still played at concerts). The bell tower lost its spire to a lightning strike in 1572 and was never rebuilt, which explains the church's curiously stunted profile.