Yedigoller means "Seven Lakes", and the name is nicely literal. The national park protects a pocket of landslide lakes in thick forest north of Bolu, with walking paths linking water, viewpoints, and picnic clearings.
Autumn is the show season, when the beech, oak, and hornbeam turn the park into one of Turkey's best-known leaf-colour trips. The road from Bolu can be slow and is not always the best winter approach, so check conditions before treating it as a casual drive.