Located in the Parc Elisabeth atop the Koekelberg hill, the National Basilica of the Sacred Heart is popularly known as the "Koekelberg basilica." It was constructed at the initiative of King Leopold II, who sought to build an imposing church dedicated to the Sacred Heart, in emulation of the one found in Montmartre in Paris, to commemorate the 75th anniversary of Belgian independence. The king laid the foundation stone in 1905, but the church was not consecrated until 1951 and was not fully completed until 1969. Cost concerns led to changes in the original neo-Gothic design. New plans by architect Albert van Huffel (1877-1935) were implemented between 1926 and 1935, which, together with later work, led to the completion of a structure that embodies a composite of different styles and materials. The massive brick and reinforced concrete church features two slender towers and a green copper dome that rises 90 m / (293 ft.) above the esplanade in dominating the city's northwestern skyline.
Historical Dictionary of Brussels. Paul F. State.