This province is as well in size as in population the largest of the four area's. It's capital Heraklion, in ancient time called Candia, has over 160.000 inhabitants and is full of life. The city, also called 'small Athens' is a very busy, lot's of traffic, shops and restaurants. But you will find some very nice squares, old buildings and it is surrounded by ancient walls. Not a real beautiful city but very lively and sure worth a visit!
South of the city is the world famous palace of Knossos, the ancient city of the king of Minoan. A guided tour is of coarse on top of your list.
About 15 miles east of Heraklion is a village called Gouves. Besides nice beaches there is a spectacular sea-aquarium.
Even more to the East are Hesonisos and Malia. Two very known but also crowded centers of tourism.
In the South of the province lies Festos, like Knossos an old Minoan city. Close to it lies Matala, known for it's cave-graves where the hippies lived during the 70-ties