On the right side of the building exterior.

A marble inscribed plaque.

The memorial remembers the 88th Infantry Division's Headquarters location while it was stationed in Italy post-World War 2 to guard the disputed border between Italy and Yugoslavia.  The 88th 'Blue Devils" Headquarters was located in this building from 1945-1947. The memorial also remembers the soldiers of the Division lost during WW2.

From the 88th Division Association website:
 
The 88th Infantry Division in Occupation and the Free Territory of Trieste Trust Period from 1947 to 1954.
 
"TRUST" stands for Trieste United States Troops, the 5,000 man U.S. contingent based in the Free Territory of Trieste created in 1947. The Free State was established in 1947 in order to accommodate an ethnically and culturally mixed population in a neutral country between Italy and Yugoslavia.
 
After the war, the 88th Infantry Division on occupation duty in Italy guarded the Morgan Line from positions in Italy and Trieste until 15 September 1947. It was then withdrawn to Livorno and inactivated. The 351st Infantry was relieved from assignment to the division on 1 May 1947 and served as the main component of a garrison command in the Free Territory of Trieste, securing the disputed border between Italy and Yugoslavia.
 
The command served as the front line in the Cold War from 1947 to 1954, including confrontations with Yugoslavian forces. In October 1954 the territory was ceded to Italy and administration turned over to the Italian Army.
 
TRUST units, which included a number of 88th divisional support units, all bore a unit patch which was the coat of arms of the Free Territory of Trieste superimposed over the divisional quarterfoil, over which was a blue scroll containing the designation "TRUST" in white."

See site  Trieste- Miramare Castle (Castello di Miramare), US Army TRUST Unit /88th Infantry Division Remembrance Monument memorial for more on this topic.

The plaque is inscribed in Italian and English.  The English reads:

Symbols of the 88th Infantry Division and "TRUST" 

"TO HONOR AND PAY TRIBUTE TO THE AMERICAN SOLDIERS OF THE U.S. ARMY 88TH INFANTRY DIVISION 'BLUE DEVILS' WHO WERE STATIONED IN GORIZIA AND VENEZIA GIULIA FROM OCTOBER 1945 THROUGH SEPTEMBER 1947. THEY HAD THEIR HEADQUARTERS IN THIS BUILDING AND DEDICATED THEMSELVES TO RE-ESTABLISHING PEACE. DEMOCRACY AND FREEDOM IN OUR CITY, ITALY AND EUROPE. THE 88TH DIVISION SUFFERED 15,173 CASUALTIES IN THE ITALIAN CAMPAIGN.

88th Division Association                                                                                                                                      VFW Post 8862- Italy