The economist who found 50-year boom-and-bust cycles was executed for the discovery

In the 1920s, Soviet economist Nikolai Kondratiev studied a century of prices, wages and trade data and proposed that capitalist economies move through long waves of roughly 40 to 60 years, driven by clusters of major technological innovation. The theory undermined Soviet doctrine that planned economies would grow without limit. Stalin had him imprisoned in 1930 and shot in 1938; economists still call these long business cycles 'Kondratiev waves.'

— Nikolai Kondratiev, The Long Waves in Economic Life — 1926