The cupola of the High Italian Renaissance style mausoleum can be seen to the right of the church itself.
Friedrich's sarcophagus is located in the middle of the rotunda, alongside that of his wife Empress Victoria. As the eldest daughter of Queen Victoria, she was the former Princess Royal of Great Britain and Ireland. The tombs of two of their young sons are also interred here.
Salviati adorned the tomb with mosaics, including those on the wall showing "VRI" for Victoria Regina Imperatrix, which are now missing. As seen from the recent picture above, compared to the interior in 1931 the entire lower level has been refaced in black marble. The interior of the dome is still said to contain the mosaics of alternating angels and palm trees; however, entrance to the mausoleum is restricted and no photographs have been found.
Barr, Sheldon. Venetian Glass Mosaics: 1860-1917. London: Antique Collectors' Club, 2008. 127.
Stefan Hintz's flickr Photostream