The Holy Trinity Cathedral stands at the corner of Mariánske námestie, its Baroque bell tower visible from most of the old town. The church itself dates from the 14th century, with later Gothic and Baroque additions that create a satisfyingly layered interior. The nave is tall and relatively austere, with fine carved altarpieces and some good Gothic stonework.
The free-standing tower beside the cathedral is older than the current church façade and was originally part of the town's fortification and fire-warning system. It can be climbed for views over the square and the surrounding rooftops. The cathedral was elevated to its current status only in 2008 when Pope John Paul II's reorganisation of Slovak dioceses created the Diocese of Žilina.