The excavation of the building's diaphragm walls, which extend almost 25 meters into the ground, has just been completed. The next stage of the investment, led by Polski Holding Nieruchomości, is the construction of three underground levels. The building is being built in the very center of Warsaw at 36 Świętokrzyska Street. Due to the dense development of the street and the proximity of the second metro line, earthworks will be carried out using the "under-ceiling" method. First, the ceiling will be constructed, supported by a temporary structure of steel columns. Then, once the ceiling has been adequately strengthened, earthworks using heavy equipment can begin beneath it. Two of the office building's three underground levels will feature parking for over 140 cars. Level -1 will house commercial and retail units, as well as a direct passageway connecting the building to the Rondo ONZ metro station. Work on the underground levels will last until the third quarter of 2020.