Only a handful of tornadoes each year cause loss of life and/or significant property damage- and such storms are certainly a significant part of American history. But a particularly costly storm in 1948 not only made history, it changed our very understanding of tornadoes themselves, resulting in the first tornado forecast.
The first class of nuclear submarines were a learning experience for the Soviet Navy. The November class boats experienced numerous difficulties and accidents, culminating in what has been described as a potential “Underwater Chernobyl."