Complex sentence: The Alexander III Commemorative egg is one of the eight Imperial Fabergé eggs that are currently missing; and one of only two lost eggs for which a photograph exists, the other being 1903's "Royal Danish" egg.
Split into simpler sentences: The Alexander III Commemorative egg is one of the eight Imperial Fabergé eggs that are currently missing; and one of only two lost eggs for which a photograph exists. The other being 1903's "Royal Danish" egg.