This red-brick cathedral is one of the country's most interesting Gothic monuments. The inside has been completely whitewashed and reflects the light that pours in through the high windows onto the chancel (15C). The transept and nave with remarkably high vaults date from the 13C, the bronze baptismal fonts from the late 15C, and the Baroque pulpit from 1636. But the main treasure is without a doubt the Sieseby organ, whose clear, smooth notes can often be heard.