The apartment is in the center of heraklion. You can visit the natural history museum of Crete. Also the museum of history and if you have kids there are many of public playgrounds and bikes exercises for free. The local market is 5 minutes walking from the apartment. Also you can visit kazantzakis grave and you can take the local bus to go to local bus to go to Knossos palace.
Everything is from 5 to 10 minutes walking. You can visit everything on foot