This is actually a really old piece (Is that okay? If not, I'll remove it.)

The style used is called pointillism or stippling. Basically, you make a picture out of dots by tapping a pen (Or other art utensil) against the paper/canvas repeatedly. It can be a long process, but the effect is unique and as long as you're patient, it's fun too.

The reference I used is an actual photo my family took while on vacation and I'm afraid I've lost it, so I apologize that I can't share it.