The ruins on the low mound of Hisarlık, about 30 km south of Çanakkale, are the most famous archaeological site in Turkey. What you actually see — low stone walls, a ramp, a half-reconstructed gate, a stretch of paved street — is a palimpsest of nine cities, built one on top of another between roughly 3000 BC and 500 AD. Troy VI or VII is the candidate for the city of Homer's Iliad.
The site is best visited with a guide, who can make sense of the layers; without one it can look like a pile of stones. The excellent Troy Museum, opened in 2018 in a striking modern building near the site, is essential context. UNESCO World Heritage since 1998. Allow a half day for the site and museum together; the journey from Çanakkale by dolmuş takes around 45 minutes.