In the late 1960s D constructed a building for the Department of Housing and Urban Development. A portion of the footings extended beyond HUD's boundary line and into P's property. This encroachment, consisting of concrete with steel reinforcing bars, ran along the common boundary line for approximately 240 feet. It extended 1 1/2 to 3 1/2 feet into P's property. The encroaching structure was approximately 3 feet thick and was buried 23 feet below the surface. On June 11, 1971, during excavation for the construction of P's building, the encroachment was discovered. After demand, D contracted for the removal of the encroachment during the month of July 1971. Construction resumed following such removal, and P's building was completed on June 25, 1973. The complaint was filed on June 21, 1974. The trial court granted D summary judgment based on the three-year statute of limitations. P appealed.