St Mary's Church is Celle's old town church, begun around 1300 and later reshaped with Baroque interiors. Its ducal crypt ties it closely to the House of Welf, while the altar, organ, and painted vaulting give the interior more warmth than the plain exterior suggests.
If the tower is open, the climb is a good way to read the town: palace, market, old roofs, and the green edge of the parks all sit close together.