Millennium Dome (London)

The Millennium Dome stands as the pinnacle of wasted potential, a £789 million structure that promised innovation but delivered emptiness. Its cavernous interior, designed without cohesive wayfinding, overwhelmed visitors with confusing layouts and sparse, soulless exhibits under the iconic but impractical roof. This misstep cost 30% more than the average London venue project of its era, yet #2 Olympic Stadium Montreal—at least—had a functional sports purpose. The Dome failed from day one, earning savage reviews in 2000 and cementing its status as a monument to overpriced ambition.