Dominican Hill Retreat House

In 1911, American friars of the Order of Preachers (commonly known as "Dominican Order") along with a few Spanish members made plans for the construction of a vacation house for them and the nuns of their order in Baguio. One of the members of the order, Fr. Roque Ruaño, O.P., the same architect of the main building of the current campus of the University of Santo Tomas, designed the building. A 17-hectare hill property was acquired from Americans who reside in Baguio and construction is said to have started in 1913 and was supervised by Ruano himself. It was then inaugurated in May 1915. To take advantage of tax exemptions, the order set up a seminary named Colegio del Santissimo Rosario on June 1915 but due to the very small enrollment, the school closed two years later and the building was reverted to its original use. The hill where the building stands was christened as "Dominican Hill".

During World War II, the people fleeing from the Japanese sought refuge within its walls. Japanese forces invaded the property and turned it into their headquarters, making it as the last bastion and garrison of the Japanese Imperial Army. Their secret police known as the Kempeitai, committed barbaric acts in the place such as torturing, raping, and decapitating priests, nuns, as well as refugees. During the liberation of the Philippines in April 1945, the American forces bombed the place and partially hit the right wing of the building while Japanese forces committed suicide. Between 1945-1947, the building underwent restoration.

One of the corridors of the Dominican Hill Retreat House. The former hotel's fountain can be seen in the far left.

Diplomat Hotels, Inc. acquired ownership of the property in 1973 and remodeled thoroughly the interior into a 33-bedroom hotel but still retaining the unique features which was earlier established by the Dominican friars. The hotel was managed by Antonio Agapito "Tony" Agpaoa, a Baguio-based entrepreneur and faith healer famous for psychic surgery. Agpaoa suffered a heart attack and was diagnosed with brain hemorrhage in the 1980s. He died in 1987 of the ailments. Since his death, the hotel ceased operations and was abandoned. Following its abandonment, the place was looted and sacked. The building also sustained significant damage during the 1990 Luzon earthquake.