Today's Guardian looks at Veliko Turnovo, which it describes as "Bulgaria's best kept secret". I have no argument with most of the content of the article, but I think the "best kept secret" line is misleading and likely to lead to disappointment. I like Veliko Turnovo and often recommend that people visit it, but I would never describe it as a "hidden treasure". It may not attract the mass-market tourism of the Black Sea coast or the ski resorts, but it's still quite a touristy place.
More about Veliko Turnovo on Balkanology