PHOTO: A.P. KARPINSKY RUSSIAN GEOLOGICAL RESEARCH INSTITUTE

Built for the Soviet Union's pavilion at the 1937 International Exposition of Art and Technology in Paris, the bejeweled, 50,000-piece "Map of Industry" took 667 workers 11 months to create. Moscow was represented on the 19-by-15-foot chart by a ruby and a hammer-and-sickle made of diamonds, while other cities were signified by gilded silver stars inset with artificial rubies. Seas were denoted by lapis lazuli, mountains by jasper, and industries by rubies, emeralds, and topazes. Insured for $137 million in 1937, the 3.5-ton map would be worth roughly $2.5 billion today.