Saint Nichola's Cathedral, also known as the Ljubljana Cathedral, is the main church of Ljubljana (maybe side-by-side with the one at Prešeren Square). It is located in the heart of the Old Town and you can easily spot its twin towers from almost anywhere in the city center.

I recommend walking inside to see the beautiful frescoes and interior. One of the main highlights of Saint Nichola's Cathedral is the main door which shows the history of Slovenia. These impressive bronze doors were added in 1996 when Ljubljana received a visit from Pope John Paul II.