The Forte Tre Sassi is located at an elevation of . It was constructed by Austrians in 1897 during the Austro-Hungarian period on the Passo Valparola. Situated between Sass de Stria and Piccolo Lagazuoi, dominating the passage between the Passo Falzarego and Val Badia in South Tyrol (Alto Adige), it was part of the large complex of Austrian fortifications built on the Italian border in the late 19th and early 20th century. Rendered unusable due to a bombing by the Italians on 5 July 1915, the ruins remained in a state of disrepair until the advent of the 21st century, when the fort was restored by the local administration of Ampezzo, with the assistance of the Lacedelli family.