Unirea College is a historical monument and was built in January 1866, the first unit of secondary education in this area and among the first in Romania. The school functioned without its own place until 1880, when the construction of the building began and the name was changed from Alexandru Ioan Cuza in Unirea Gymnasium. The next few years, the gymnasium turned into a high school, which in 1900 was moved to the present building.

During the years of German occupation (1917-1918), the High School was transformed into a hospital and the school stopped functioning. In the interwar period, the material ground of the school has developed with the setting up of an amphitheater, a library room, and in 1928 was born the first museum of history and ethnography of the area, initiated by Professor Alexandru Arbore.

The World War II and the earthquake of 1940 caused damages to the building, several books and teaching materials were destroyed.
During communism, the forced industrialization process resulted in a decline period of the high school, being converted from theory high school in automotive industry high school.

In the high school worked the Societatea Literara (Literary Society )(1898), Liga Culturala (League of Culture), Revista noastra (Our Magazine), Milcovia (1930), the first museum of history and ethnography of the region of Putna. Great personalities of Romanian science and culture were teachers or students at the Union College: C.G.Giurascu, D.Caian, Ovid Densusianu, S. Mehedinti, Anghel Saligny, Ion Mincu, Duiliu Zamfirescu, Virgil Huzum. The building in which the highschool currently functions was built at the end of the last century in the year 1899, being included in the category of national architectural monuments.