1) The first smartphone, the IBM Simon, was introduced in 1992 and featured a touchscreen, email capabilities, and apps such as a calendar and calculator.

2) In Norse mythology, Ragnarok is a cataclysmic event that signifies the end of the world. It involves a series of apocalyptic battles and natural disasters, leading to the destruction of the gods and the world as it is known. From the ashes, a new world and a new generation of gods emerge.

3) Mount Everest, located in the Himalayas, is the highest peak on Earth, with an elevation of 8,848 meters (29,029 feet). It is a popular destination for mountaineers and represents a significant challenge due to its extreme altitude and harsh weather conditions.

4) The Industrial Revolution, which began in the 18th century, brought about significant changes in agriculture, manufacturing, mining, and transportation.