After the Franco-Prussian War of 1870, it was proposed to construct a church to the Sacred Heart on the butte Montmartre. Although originally the fund raising was by public subscription, in 1873, the National Assembly declared its construction to be a state undertaking. Of the 78 entries in the competition for its design, the one chosen was by the architect named Abadie. He was already well known for his restoration of the St-Front Cathedral in Périgueux.
The plans for the new basilica called for an edifice of Romano-Byzantine style, and the first stone was laid in 1875. Abadie himself died in 1884 with only the foundation having been completed.
Completed in 1914, it was not consecrated until 1919 after World War I had ended. The final cost was 40 million francs. Since 1885, there has been perpetual adoration and worship within.
The interior of the church contains one of the worlds largest mosaics, and depicts Christ with outstretched arms. The nearby bell tower contains the ``Savoyarde''. Cast in Annecy in 1895, it is one of the worlds heaviest at 19 tons. (paris.org)