With the construction of the Sacré-Coeur, all the butte was bubbling with excitement. The French National Assembly voted for the basilica construction, on July 23th 1873. After a 5 months contest, they chose the Romanesque-Byzantine plan made by architect Paul d’Abadie among 80 other models. And on June 16th 1875, they laid down the first stone of a huuuge building work...
Oh, by the way: in this stone, the archbishop of Paris, who conducted the ceremony, put a medallion representing France giving the basilica to Jesus’ Sacred Heart... and also the ceremony official report, written on paper. Well, now, serious things could begin. But the building works dragged on... First, they started to analyse the soil.
Which looked like a real Gruyère cheese, here, because of the several quarries! Here, on butte Montmartre, it was like in the Buttes Chaumont: we had plaster quarries everywhere, exploited since the Gallo-Roman era! I’ll leave you to imagine the state of the sub-soil... We had, at the time of the basilica’s construction, about 300 km of galleries.
Besides, in those ones, the famous anatomist Cuvier found the fossil bones of the creature today known as Montmartre possum! He also founded here the modern palaeontology. In short! Let’s get back to the butte. Foundations and reinforcement works took months. They had to raise more than 80 wells, 30 metres deep, full of concrete and linked together by arches, which were also used as pillars.
The building works took ages, but they were expensive, too. There was a way to find a solution: to let people buy one or several building stones. They had choice between several models, from 120 to 500 francs, says the book Guide de Paris mystérieux (ed Tchou).
They could also buy columns for 1000 of 5000 francs... The most expensive models were carved with the generous donors’ names, of course! Finally, the building works carried on: the crypt began in 1878, the basilica in 1881. Everything was inaugurated in 1891...