My stepfather has lost his shit and gone from accountant to flat earther. This has evolved from glass dome above the earth that caused the Challenger explosion to some new shit. Enter the ２０４０ Ｐｈｏｅｎｉｘ Ｅｖｅｎｔ. Every 140 years there's a cataclysmic event which changes the fundamental nature of the planet. This cycle is so powerful that it actually destroyed the Mayan civilisation. In 2040 it's due to happen again and the ONLY place on earth that will be safe is Egypt.
But what was the last thing that happened in 1900, you might ask.
The 1908 Tunguska Event in which an asteroid air burst above Siberia and killed a few reindeer herders.
But 1908 is 8 years after the 140 year cycle and 1900 was pretty uneventful, you might say.
I knew a similar individual a a former workplace. Aside from flat earth stuff he believed that cancer is caused by bad generational karma, that any sexuality apart from straight is the result of childhood abuse, that females want to steal his vital essence via sex, that modern medicine is a scam and the best way to heal is through fasting and meditation, that the Bronze Age Collapse was caused by the fall of Atlantis, and a whole bunch of other stuff I can't remember right now.