They are very distinct and easy to notice once you know their unique leaf shape!
I was very surprised to find myself in a courtyard of olive trees, and very excited to see some up close! I've seen olive trees, mostly from afar, so I'd never had the chance to study their leaf shape or get a better idea of what they look like. They're not common in my home state, as it is a bit too cold and rainy for them in Oregon, so it was really interesting to examine an unfamiliar plant. Since I saw the ones in the church courtyard, I've also seen them in planters outside restaurants in Florence! I'd probably been walking past them for the last two weeks as I didn't know how to recognize them yet! It's always fun to learn about new species of plants and be able to recognize them in different places!
Olive trees are actually a plant native to Italy! While they can be found all over, they grow best in the Mediterranean, Africa, and parts of Asia, and are most commonly found growing in these warmer climates. The Olea Europaea variety, which I saw, is specifically native to the Mediterranean Basin (in which Italy is located). Olive trees grow naturally out in the wild, but are also commonly seen growing in pots. Ones like the ones I saw are usually considered to be dwarf variety, meaning they don't get very tall and are often grown in pots.