Places in Greece break into beaches, viewpoints, archaeological sites, churches, wineries, museums, and traditional villages.
Most iconic sights on Santorini are free (Oia Castle, the Fira-to-Oia caldera walk, Pyrgos Kasteli). Paid archaeological sites like Akrotiri and Knossos are best visited before 10 AM.
Cruise-ship days (Tue–Thu in summer) crowd Oia and Fira midday; plan village walks for early morning or late afternoon.