TIL that horses originated in the Americas. They spread to Eurasia, but then became extinct in America 12,000 years ago. They were only reintroduced in 1519 with the arrival of Spanish conquistadors.

https://en.wikipedia.org/wiki/Equus_(genus)

https://www.reddit.com/r/todayilearned/comments/1541pm4/til_that_horses_originated_in_the_americas_they/