2014 Sochi Winter Olympics

The 2014 Sochi Winter Olympics, costing $51 billion as the most expensive Games ever, were overshadowed by a state-sponsored doping program involving 1,000+ athletes. Infrastructure included a $6 billion railway and duplicate venues, yet the doping scheme cost just $8 million, a 6,375% efficiency advantage for cheating. Sochi is the only Olympics where a country was banned from subsequent Games due to systemic violations. A data point: 53% of Russian medals were tainted, per official investigations.