Keldby is the second of the three Møn churches with frescoes by the Elmelunde Master and his school, and the most extensive of the three: ceilings, walls, and arches are covered with scenes from Genesis, the life of Christ, and a hectic Last Judgement complete with leering demons and the saved being weighed. The work dates from the late 15th century and is in remarkable condition.
The church itself is plain Romanesque, built in the 12th century, with a later Gothic tower. It sits in a tiny village a few kilometres west of Stege on the old road across the island. Visitors can drop in during the day — the door is usually unlocked outside service hours — and there is a small leaflet inside explaining each panel.