Built by the Turks as part of the town defenses, and later used as a prison, this sturdy stone pentagon now houses a smattering of ancient artifacts unearthed in caves and other ancient sites around Rethymnon. Here you will not come across the Minoan frescoes and jewels that bedazzle visitors to the Archaeological Museum in Iraklion, but the prehistoric stone tools, figurines, Roman oil lamps, and other finds warrant a passing glance, if only as intriguing reminders that Crete has been inhabited for millennia.