the 1920s was incorporated in the in its basic form, and was subsequently reexamined in numerous drafts and proposals. Real construction practice often contradicted the plans: new buildings erected in the center of Moscow often blocked or narrowed the planned avenue. In 1940, the city approved a revised plan. All buildings between the palace and the Kremlin, including the Moscow Manege, had to be demolished. The Alexander Garden would be leveled into a flat and straight boulevard. The Pushkin Museum building, which partly obstructed the course of the Alley, would be moved north to Gogolevsky Boulevard. Most of it would be absorbed into the palace plaza. The plaza would extend far south-west along the axis of the Alley, and north-west into present-day Arbat District. The Zamoskvorechye island west of the House on the Embankment would disappear, making way for a wide reflective pool. The tip of the island would become a base to the memorial of the Chelyuskin and the projected Pantheon of the Aviators. After World War II, the Ivan Zholtovsky workshop proposed an even larger, and certainly unreal, redevelopment plan for the central squares. Nothing ever came from these fantasies except for the construction of the New Arbat Avenue in the 1960s. Construction and demolition (1933–1942) A geological survey of the site began in 1933 and continued into 1934. Drilling to depths of confirmed the feasibility of construction. The uppermost limestone sill was too thin to carry the main building's weight, but the second one, below the water level, was sufficiently solid. Groundwater in the area contained very little sulfates and chlorides, and was almost always still, thus concrete degradation was not a significant concern. In the second half of 1934, the builders drilled hundreds of boreholes around the perimeter of the site and pumped hot bitumen into the ground. This formed a watertight vertical curtain extending from the surface to the load-bearing sill, which allowed safe excavation below the river level. Blasting and excavation commenced in January 1935, and continued for more than three years. To clear the pit down to the bedrock, the workers removed of rock and of soft soil. The core's concrete foundations, consisting of two concentric rings with an external diameter of , were completed in January 1938. In a related but independent development, the nearby Dvorets Sovetov ("Palace of the Soviets") metro station, placed just outside the watertight perimeter, was built in