Mudurnu is a nice town to visit, but in my eyes no world heritage.

You can walk there and see nice things, the little museum with old stuff is nice.

But what is really worth the drive is this: Burj Al Babas Villa (check the images on google) just outside Mudurnu if you drive to Beyparazi.

Certainly no world heritage, but one of the most remarkable things i have ever seen ....