For me it is the fact that our blood contains iron. I earlier used to believe the word stood for some ‘organic element’ since I couldn’t accept we had metal flowing through our supposed carbon-based bodies, till I realized that is where the taste and smell of blood comes from.
Not really. 1896 was a leap year, but 1900 was not.
The leap year after 2096 will be 2104.
Edit: an interesting way to put this is, 2000 was the only year in 4 centuries where the year starting the century was a leap year. Next such occurrence will be in 2400