The St Nikolaus hospital was founded in 1447 by Cardinal Nicholas of Kues (1401-1464), a humanist and theologian himself born in Kues. It was built to house 33 old people in need (Christ's age when he died), and this tradition is still observed to this very day. The Gothic cloister and chapel are worth seeing. Inside, admire the beautiful 15C altarpiece, a bronze copy of the cardinal's tombstone, and the tombstone of Clara Cryftz, the prelate's sister.