What is an example of an event that caused long-term historical effects?

theodore roosevelt challenged william to a duel, whoever won, got their policy sent to congress. it ended up in a stalemate, and both men were injured and sent to the hospital.

aug 15, 2012 - although van leeuwenhoek was not the inventor of the microscope, he advanced it more he loved to grind and focus a new lens in order to see the unseen world. most of leeuwenhoek's microscopes were silver. in a simple but significant experiment (1668), he demonstrated that worms found on