What critical structural issue led to the near-collapse and subsequent emergency reinforcement of Frank Lloyd Wright's Fallingwater house in the 1990s?

Frank Lloyd Wright's Fallingwater is considered one of the most iconic residential buildings in American architecture. However, this masterpiece nearly collapsed shortly after construction. Test your knowledge of this famous architectural product recall that required extensive structural reinforcement to save the landmark.

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

The main cantilevers had deflected nearly 7 inches and were on the verge of structural failure
The waterfall beneath the house had eroded the foundation, causing the building to sink unevenly
Wright's innovative glass corner windows lacked proper support, creating dangerous stress points
The flat roof design failed to account for snow loads, causing ceiling cracks throughout the structure