Ouzo it originates from the 14th century, from Tsipouro which is another original greek drink, only Ouzo was anise flavored. Ouzo is a protected designation of origin product, which means that the name "Ouzo" its prohibited to be used outside of the Greek country.
It is very strong, and better drink it with water, it is usually preferred with Ice. It is clear like water, but when you mixed with water it loses its transparency and becomes semi-transparent white.
Ouzo is the best when consumed with seafood (almost never on its own), and especially with " mezedes " (a variation of small plates with various types of traditional rhodian foods, either meat or seafood oriented but not both) Try a cold glass of ouzo combine with " octopus " or Kalamari or both of them , with a Greek salad and tzatziki sauce. Is the perfect combination for ouzo.

You have to try this local drink when you visit Rodos (even if you dont like it right away, give it a chance, you may like it a lot after you drink it), but be careful in the beginning, one or two glasses of Ouzo may get you drunk without you noticing... At least it doesn't leave you with a big headache like other drinks would....