Santorini is one of the most famous Greek Islands with its panoramic views, white houses, incredible sunsets, gorgeous beaches, fun nightlight, and the ruins of ancient Thira.
Athens is the best place to get a glimpse into ancient Greece. Athens is also a relatively cheap city compared to other capitals in Europe and has many beautiful things to see.
Thessaloniki features many exciting places, including ancient ruins, beautiful museums, unique restaurants, and picturesque sandy beaches.