Cartier adapts the archaic method of filigree, to make one of the most sumptuous watches: the Ronde Louis Cartier  XL. Requiring at least a month to complete, the Ronde Louis Cartier XL with panthers motifs  is available in a limited edition of 20 pieces, all made at Cartier’s Maison d’Art in La Chaux-de-Fonds in Switzerland. Filigree is a craft…