- The Mesozoic Era is the second-to-last era of Earth’s geological history, lasting from about 252 to 66 million years ago, comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles, such as the dinosaurs; a hot greenhouse climate; and the tectonic break-up of Pangaea. The Mesozoic is the middle of the three eras since complex life evolved: the Paleozoic, the Mesozoic, and the Cenozoic.
- Snoqualmie Falls (waterfallsnorthwest.com)
Snoqualmie Falls is among the largest and most significant waterfalls in the United States. Situated along the Snoqualmie River in the town of Snoqualmie, the falls plunge a into a huge amphitheater carved in ancient volcanic bedrock. Officially Snoqualmie Falls has a height of 268 feet, however lidar data suggests this measurement to be that of the hydroelectric system, rather than the falls itself, and that the waterfall itself is about 10-12 feet shorter. The natural volume of the Snoqualmie River, coupled with the great height of the falls makes it one of the most powerful waterfalls in North America. However, that power was too tempting a prospect for intrepid engineers, and in July of 1899 the Snoqualmie Falls Hydroelectric plant went online - the first hydroelectric facility in the world to be built entirely underground. In 1910 a second powerhouse (this one above ground) was constructed downstream of the falls, which was greatly expanded again in the late 1950s.
- Cretaceous–Paleogene extinction event (Wikipedia)
The Cretaceous–Paleogene (K–Pg) extinction event, also known as the Cretaceous–Tertiary (K–T) extinction, was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs. Most other tetrapods weighing more than 25 kilograms (55 pounds) also became extinct, with the exception of some ectothermic species such as sea turtles and crocodilians. It marked the end of the Cretaceous period, and with it the Mesozoic era, while heralding the beginning of the Cenozoic era, which continues to this day.