The Sacred Temple of San Nicolò, better known as the Ossario Temple of Udine, is located in the central Rotonda XXVI Luglio at the end of Viale Venezia. With its imposing dome, it is visible even from a distance and is divided into its own ossuary, which houses the remains of 21,500 fallen soldiers in the Great War in Friuli-Venice, and the parish church of San Nicolò, a function for which the building was originally planned was.
Work began in 1925 on the project of architects Provino Valle and Alessandro Limongelli, but two years later the decision was made to transform the church into a place to collect the thousands of corpses in the war cemeteries between the Isonzo and Tagliamento rivers. The initial decisions were partially revised and a grandiose crypt was built under the church, which still houses the fallen, about 5,600 of whom are unnamed. The identified corpses are arranged in loculi along the walls, while the unknown are in two large common graves, on which the epigraph "Et nomen una cum sanguine pro Patria dedimus" ("For the fatherland, together with the blood, we also have the name offered") can be read. In the crypt there is also a bronze statue dedicated to the many fallen and miscellaneous of the Julia and Friuli divisions as well as 300 fallen soldiers of the Second World War.
The external facade of the temple clearly recalls the Great War with the placement of four large statues by Silvio Olivo, representing the Alpine, the Fante, the Aviator and the Sailor. Inside the parish church, on the other hand, there are 14 side chapels, each dedicated to a station of the "Way of the Cross" with formalities by Giannino Castiglioni, which was already written in the chapel of the monastery of Redipuglia.