The hectic capital of Crete
Heraklion, the capital of Crete, combines the lively atmosphere of a port city with a rich history dating back to the Minoan civilization. In its center you will find the Venetian fortress of Koules, bustling streets with taverns and shops, and one of the most important archaeological museums in Greece. The city is also a great starting point for visiting the Palace of Knossos, one of the most famous monuments of the entire island.
However, if you are not planning to visit museums, I would avoid the city or just walk around for a few hours. The city is really hectic in terms of traffic, motorbikes are passing from everywhere and they cram even into the smallest gap. There are also not many places to swim in the sea in the city, and when there are, they are near a busy road. The bus service around the city is relatively efficient and will take you to the airport reliably.