The White Sister by F. Marion Crawford

The lay sister was right. The great powder magazine at Monteverde had been blown up, but by what hands no one has ever surely known. The destruction was sudden, complete, tremendous, for a large quantity of dynamite had been stored in the deep vaults. Today, a great hollow in the side of the hill and near the road marks the spot where the buildings stood. Many stories have been told of the catastrophe; many tales have been repeated about suspicious characters who had been seen in the neighbourhood before the fatal event, and for some of these there is fairly good authority.

All those who were in the city when the explosion took place, and I myself was in Rome at the time, will remember how every one was at first convinced that his own house had been struck by lightning or suddenly shaken to its foundations. Every one will remember, too, the long and ringing shower of broken glass that followed instantly upon the terrific report. Every window looking westward was broken at once, except some few on the lower stories of houses protected by buildings opposite.